ALBERT

Description:    The recovery of native communities after cultivation may be constrained by (a) the failure of species to reach a site or (b) their failure to survive once there. Although seed addition is a common method to test for seed versus microsite limitation, most studies do not follow populations beyond seedling establishment, nor do they measure seed dispersal. We examined dispersal across native grassland/old field boundaries and investigated the relative importance of seed and microsite limitation across multiple life-history stages and generations. Seed trapping showed little movement of native seeds into old fields and that most species had extremely localized dispersal. Consequently, there was no pattern of seed density with distance from boundaries, and similarity between the seed rain and standing vegetation was moderate to high. Seed addition showed that two annual species were able to establish in all, and flower in most, subplots in the first year, and that seedling establishment increased with sowing density, consistent with seed limitation. However, the relative importance of microsite limitation increased over the lifespans of the species. Density dependence reduced the number of flowering plants, resulting in a large decline in seedling density in the following generation. This decline continued so that the initial positive effect of sowing density on seedling numbers disappeared by the fourth generation and hence the persistence of populations is uncertain. Thus, by monitoring seed dispersal and following experimental populations beyond seedling establishment, we showed that dispersal limits species distributions, but microsite plays an important role in limiting population growth and persistence. Content Type Journal Article Category Community ecology - Original research Pages 1-12 DOI 10.1007/s00442-012-2285-0 Authors Andrew J. Scott, Department of Botany, La Trobe University, Bundoora, Melbourne, VIC 3086, Australia John W. Morgan, Department of Botany, La Trobe University, Bundoora, Melbourne, VIC 3086, Australia Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Variation in patterns of propagule establishment (recruitment) has important effects on population dynamics and the structure of some communities. Most experimental studies have varied recruitment by changing the nature of a single event early in community development, but recruitment can also vary from steady rates of arrival to highly episodic ‘pulse’ events, causing differences in the temporal spacing of individuals recruiting into patches. We examined whether two different temporal patterns of recruitment of sessile invertebrates affected temperate marine communities in southeastern Australia in two experiments that were run at different times at the same site and that manipulated several different species. Target species entered communities as either a single pulse of recruits within a 2-week period or steady input of the same total number of recruits over a longer time period (5–6 weeks). The pattern of recruitment had variable effects on community structure. The colonial ascidian Botryllus schlosseri did not have a strong influence on community structure whether it recruited in a single pulse or steadily. The cover of B. schlosseri was higher when recruitment occurred as a single pulse. In a second experiment, botryllid ascidians caused changes in the composition of communities when they recruited steadily compared to when they did not recruit or didemnids recruited, but caused no differences in communities when they recruited in a shorter pulse. In contrast, recruitment frequency of didemnid ascidians had little effect, though their presence/absence caused community differences. Though we found that different temporal recruitment patterns can alter community composition, the life history and ecology of particular taxa as well as differences in environmental background processes are likely to influence the strength of these effects. Content Type Journal Article Category Community ecology - Original research Pages 1-11 DOI 10.1007/s00442-012-2284-1 Authors Michael A. Sams, Department of Zoology, University of Melbourne, Victoria, 3010 Australia Michael J. Keough, Department of Zoology, University of Melbourne, Victoria, 3010 Australia Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Separating plastic from ontogenetic and growth-limiting responses of plants to changes in resource availability can be challenging because there are a total of eight combinations of these three types of responses. These can, however, be uniquely distinguished on plots of root:shoot ratios against total biomass through time. We used this approach to separate ontogenetic, plastic, and growth-limiting responses of wild rice ( Zizania palustris L.) to changes in nitrogen, phosphorus, and light availabilities. Relative growth rate was limited primarily by nitrogen but responded to increased light and phosphorus after nitrogen limitations were alleviated. Nitrogen addition increased relative growth rate because it simultaneously increased unit leaf rate, specific leaf area, and leaf weight ratio. Increased light did not change relative growth rate because decreased specific leaf area and leaf weight ratio compensated the increased unit leaf rate. Phosphorus did not change either relative growth rate or its underlying components. Plants responded ontogenetically to increased nitrogen and light availabilities by accelerating their developmental rate, and plastically by decreasing or increasing their root:shoot ratios, respectively. Plants did not respond either ontogenetically or plastically to increased phosphorus availability. Ontogenetic changes in growth can be separated from plastic and growth-limiting responses by plotting root:shoot ratio against total biomass in the context of the eight possible responses identified above, and also by examining how the underlying components of relative growth rate respond. Content Type Journal Article Category Physiological ecology - Original research Pages 1-12 DOI 10.1007/s00442-012-2296-x Authors Lee Sims, Integrated Biosciences Program, University of Minnesota Duluth, 1035 Kirby Dr, Duluth, MN 55811, USA John Pastor, Department of Biology, University of Minnesota Duluth, 1035 Kirby Dr, Duluth, MN 55811, USA Tali Lee, Department of Biology, University of Wisconsin Eau Claire, Phillips 330, Eau Claire, WI 54702, USA Brad Dewey, Department of Biology, University of Minnesota Duluth, 1035 Kirby Dr, Duluth, MN 55811, USA Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Natural populations often face multiple mortality sources. Adaptive responses to one mortality source might also be beneficial with respect to other sources of mortality, resulting in “reinforcing adaptations”; or they might be detrimental with respect to other sources of mortality, resulting in “conflicting adaptations”. We explored these possibilities by testing experimentally if the responses of guppies ( Poecilia reticulata ) to the monogenean ectoparasitic worm Gyrodactylus differed between populations adapted to different predation regimes. In experimental stream channels designed to replicate the natural environment, we exposed eight guppy populations (high-predation and low-predation populations from each of four separate rivers) either to their local Gyrodactylus parasites (infection treatment) or to the absence of those parasites (control). We found that infection dynamics varied dramatically among populations in a repeatable fashion, but that this variation was not related to the predation regime of origin. Consistent with previous work, high-predation guppy females gained more mass, had lower reproductive investment, and had more but smaller embryos than did low-predation females. Relative to control (no parasite) channels, guppies from treatment (infected) channels gained less mass but produced similar numbers and sizes of embryos—and thus had a higher reproductive effort. However, no interaction was evident between infection treatment and predation regime. We conclude that parasitism by Gyrodactylus and predation are both likely selective forces for guppies, but that adaptation to predation does not have an obvious deterministic effect on host–parasite dynamics or on life-history traits of female guppies. Content Type Journal Article Category Population ecology - Original research Pages 1-12 DOI 10.1007/s00442-012-2289-9 Authors Felipe Pérez-Jvostov, Institute of Parasitology, McGill University, 21111 Lakeshore Road, Ste. Anne de Bellevue, QC, H9X 3V9, Canada Andrew P. Hendry, Redpath Museum, McGill University, 859 Sherbrooke Street West, Montreal, QC H3A 2K6,, Canada Gregor F. Fussmann, Department of Biology, McGill University, 1205 Docteur Penfield, Montreal, QC H3A 1B1,, Canada Marilyn E. Scott, Institute of Parasitology, McGill University, 21111 Lakeshore Road, Ste. Anne de Bellevue, QC H9X 3V9,, Canada Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Just as ecological indirect effects can have a wide range of consequences for community structure and ecosystem function, theory suggests that evolutionary indirect effects can also influence community dynamics and the outcome of species interactions. There is little empirical evidence documenting such effects, however. Here, I use a multi-generation selection experiment in the field to investigate: (1) how the exotic plant Medicago polymorpha and the exotic insect herbivore Hypera brunneipennis affect the evolution of anti-herbivore resistance traits in the native plant Lotus wrangelianus and (2) how observed Lotus evolutionary responses to Hypera alter interactions between Lotus and other members of the herbivore community. In one of two study populations, I document rapid evolutionary changes in Lotus resistance to Hypera in response to insecticide treatments that experimentally reduced Hypera abundance, and in response to Medicago -removal treatments that also reduced Hypera abundance. These evolutionary changes in response to Hypera result in reduced attack by aphids. Thus, an evolutionary change caused by one herbivore species alters interactions with other herbivore taxa, an example of an eco-evolutionary feedback. Given that many traits mediate interactions with multiple species, the effects of evolutionary changes in response to one key biotic selective agent may often cascade through interaction webs to influence additional community members. Content Type Journal Article Category Plant-animal interactions - Original research Pages 1-11 DOI 10.1007/s00442-012-2288-x Authors Jennifer A. Lau, Kellogg Biological Station and Department of Plant Biology, Michigan State University, 3700 E Gull Lake Dr., Hickory Corners, MI 49060, USA Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    In the present study, a high Mn twinning induced plasticity (TWIP) steel and two Al-added TWIP steels were fabricated, and their microstructures, tensile properties, and cup formability were analyzed to investigate the effects of Al addition on deformation mechanisms in tensile and cup forming tests. In the high Mn steel, the twin formation was activated to increase the strain hardening rate and ultimate tensile strength, which needed the high punch load during the cup forming test. In the Al-added TWIP steels, the twin formation was reduced, while the slip activation increased, thereby leading to the decrease in strain hardening rate and ultimate tensile strength. As twins and slips were homogeneously formed during the tensile or cup forming test, the punch load required for the cup forming and residual stresses were relatively low, and the tensile ductility was sufficiently high even after the cup forming test. This indicated that making use of twins and slips simultaneously in TWIP steels by the Al addition was an effective way to improve overall properties including cup formability. Content Type Journal Article Pages 1-14 DOI 10.1007/s11661-011-1007-2 Authors Seokmin Hong, Center for Advanced Aerospace Materials, Pohang University of Science and Technology, Pohang, 790-784 Republic of Korea Sang Yong Shin, Center for Advanced Aerospace Materials, Pohang University of Science and Technology, Pohang, 790-784 Republic of Korea Hyoung Seop Kim, Center for Advanced Aerospace Materials, Pohang University of Science and Technology, Pohang, 790-784 Republic of Korea Sunghak Lee, Center for Advanced Aerospace Materials, Pohang University of Science and Technology, Pohang, 790-784 Republic of Korea Sung-Kyu Kim, Automotive Steels Research Group, Technical Laboratories, POSCO, Gwangyang, 545-711 Republic of Korea Kwang-Geun Chin, Automotive Steels Research Group, Technical Laboratories, POSCO, Gwangyang, 545-711 Republic of Korea Nack J. Kim, Center for Advanced Aerospace Materials, Pohang University of Science and Technology, Pohang, 790-784 Republic of Korea Journal Metallurgical and Materials Transactions A Online ISSN 1543-1940 Print ISSN 1073-5623

Description:    The phenomenon of overyielding in species-diverse plant communities is mainly attributed to complementary resource use. Vertical niche differentiation belowground might be one potential mechanism for such complementarity. However, most studies that have analysed the diversity/productivity relationship and belowground niche differentiation have done so for fully occupied sites, not very young tree communities that are in the process of occupying belowground space. Here we used a 5–6 year old forest diversity experiment to analyse how fine-root (〈2 mm) production in ingrowth cores (0–30 cm) was influenced by tree species identity, as well as the species diversity and richness of tree neighbourhoods. Fine-root production during the first growing season after the installation of ingrowth cores increased slightly with tree species diversity, and four-species combinations produced on average 94.8% more fine-root biomass than monocultures. During the second growing season, fine-root mortality increased with tree species diversity, indicating an increased fine-root turnover in species-rich communities. The initial overyielding was attributable to the response to mixing by the dominant species, Pseudotsuga menziesii and Picea abies , which produced more fine roots in mixtures than could be expected from monocultures. In species-rich neighbourhoods, P. abies allocated more fine roots to the upper soil layer (0–15 cm), whereas P. menziesii produced more fine roots in the deeper layer (15–30 cm) than in species-poor neighbourhoods. Our results indicate that, although there may be no lasting overyielding in the fine-root production of species-diverse tree communities, increasing species diversity can lead to substantial changes in the production, vertical distribution, and turnover of fine roots of individual species. Content Type Journal Article Category Ecosystem ecology - Original research Pages 1-11 DOI 10.1007/s00442-012-2259-2 Authors Pifeng Lei, Faculty of Forest and Environmental Sciences, Institute of Silviculture, University of Freiburg, Tennenbacherstr. 4, 79106 Freiburg i. Br., Germany Michael Scherer-Lorenzen, Faculty of Biology, Geobotany, University of Freiburg, Schaenzlestr. 1, 79104 Freiburg i. Br., Germany Jürgen Bauhus, Faculty of Forest and Environmental Sciences, Institute of Silviculture, University of Freiburg, Tennenbacherstr. 4, 79106 Freiburg i. Br., Germany Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Species should only persist in local communities if they have functional traits that are compatible with habitat-specific environmental conditions. Consequently, pronounced regional environmental gradients should produce environmental filtering, or a trait-based spatial segregation of species. It is critical to quantify the links between species’ functional traits and their environment in order to reveal the relative importance of this process to community assembly and promote understanding of the impacts of ongoing environmental changes. We investigated this relationship using epigaeic ants in an environmentally heterogeneous region of Florida. We found evidence for environmental filtering as environmental conditions such as groundcover, surface temperature, vapor pressure deficit, and plant diversity were strongly correlated with assemblage composition. Certain species traits appeared particularly important to persistence: (1) ants in environments with less groundcover have relatively longer legs but do not differ in size, (2) ants in hotter environments exhibit greater thermal tolerances, and (3) ants in hotter and drier environments do not exhibit greater desiccation resistance. These findings show surface complexity and temperature may interact with morphology and physiology to impact the spatial distribution of ants and underscore the importance of climate change. Climate warming is predicted to alter assemblage composition, competitive dynamics, and consequently impact ecosystem processes. We suggest environmental filters acting at regional scales, as shown here, act in tandem with more frequently studied local-scale competitive interactions to delimit ant community assemblages. Content Type Journal Article Category Community ecology - Original research Pages 1-12 DOI 10.1007/s00442-012-2262-7 Authors Philipp T. Wiescher, Department of Biology, University of Utah, 257 South 1400 East, Salt Lake City, UT 84112, USA Jessica M. C. Pearce-Duvet, Department of Biology, University of Utah, 257 South 1400 East, Salt Lake City, UT 84112, USA Donald H. Feener, Department of Biology, University of Utah, 257 South 1400 East, Salt Lake City, UT 84112, USA Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Foliar nitrogen has been shown to be positively correlated with midsummer canopy albedo and canopy near infrared (NIR) reflectance over a broad range of plant functional types (e.g., forests, grasslands, and agricultural lands). To date, the mechanism(s) driving the nitrogen–albedo relationship have not been established, and it is unknown whether factors affecting nitrogen availability will also influence albedo. To address these questions, we examined variation in foliar nitrogen in relation to leaf spectral properties, leaf mass per unit area, and leaf water content for three deciduous species subjected to either nitrogen (Harvard Forest, MA, and Oak Ridge, TN) or CO 2 fertilization (Oak Ridge, TN). At Oak Ridge, we also obtained canopy reflectance data from the airborne visible/infrared imaging spectrometer (AVIRIS) to examine whether canopy-level spectral responses were consistent with leaf-level results. At the leaf level, results showed no differences in reflectance or transmittance between CO 2 or nitrogen treatments, despite significant changes in foliar nitrogen. Contrary to our expectations, there was a significant, but negative, relationship between foliar nitrogen and leaf albedo, a relationship that held for both full spectrum leaf albedo as well as leaf albedo in the NIR region alone. In contrast, remote sensing data indicated an increase in canopy NIR reflectance with nitrogen fertilization. Collectively, these results suggest that altered nitrogen availability can affect canopy albedo, albeit by mechanisms that involve canopy-level processes rather than changes in leaf-level reflectance. Content Type Journal Article Category Physiological ecology - Original research Pages 1-11 DOI 10.1007/s00442-012-2263-6 Authors Haley F. Wicklein, Complex Systems Research Center, Morse Hall, Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, 8 College Rd, Durham, NH 03824, USA Scott V. Ollinger, Complex Systems Research Center, Morse Hall, Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, 8 College Rd, Durham, NH 03824, USA Mary E. Martin, Complex Systems Research Center, Morse Hall, Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, 8 College Rd, Durham, NH 03824, USA David Y. Hollinger, Northern Research Station, US Department of Agriculture Forest Service, Durham, NH 03824, USA Lucie C. Lepine, Complex Systems Research Center, Morse Hall, Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, 8 College Rd, Durham, NH 03824, USA Michelle C. Day, Complex Systems Research Center, Morse Hall, Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, 8 College Rd, Durham, NH 03824, USA Megan K. Bartlett, Department of Environmental Science, Policy, and Management, University of California, Berkeley, CA 94720, USA Andrew D. Richardson, Department of Organismic and Evolutionary Biology, Harvard University Herbarium, Harvard University, 22 Divinity Avenue, Cambridge, MA 02138, USA Richard J. Norby, Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Hot-rolled, binary Mg-Nd alloys with compositions ≥0.095 at. pct undergo the texture weakening phenomenon that has been reported in a number of Mg–rare earth (RE) alloys. However, alloys with compositions ≤0.01 at. pct retain a strong basal texture typical of pure Mg and other Mg alloys. Measurements of intragranular misorientation axes obtained using electron backscatter diffraction (EBSD) show that more dilute alloys contain predominantly basal $$ 〈 a 〉 $$ dislocations, while richer alloys contain primarily prismatic $$ 〈 a 〉 $$ dislocations. It is suggested that this change in dislocation content is related to a change in the dynamic recrystallization (DRX) mechanism. Metastable second-phase Mg x Nd 1– x intermetallic particles are present within the alloys, and an annealing study indicates that the alloys undergoing texture weakening have grain sizes well predicted by classical Zener drag theory. Even though the more dilute alloys also contain second-phase particles, they are not sufficient to induce pinning. The promotion of nonbasal slip and the reduction in grain boundary mobility due to Zener drag are suggested as controlling mechanisms that promote the observed texture weakening phenomena. Content Type Journal Article Pages 1-13 DOI 10.1007/s11661-011-1018-z Authors Jason P. Hadorn, Materials Science and Engineering Department, University of Virginia, Charlottesville, VA 22904-4745, USA Kerstin Hantzsche, Magnesium Innovation Center (MagIC), Helmholtz Centre Geesthacht, 21502 Geesthacht, Germany Sangbong Yi, Magnesium Innovation Center (MagIC), Helmholtz Centre Geesthacht, 21502 Geesthacht, Germany Jan Bohlen, Magnesium Innovation Center (MagIC), Helmholtz Centre Geesthacht, 21502 Geesthacht, Germany Dietmar Letzig, Magnesium Innovation Center (MagIC), Helmholtz Centre Geesthacht, 21502 Geesthacht, Germany Sean R. Agnew, Materials Science and Engineering Department, University of Virginia, Charlottesville, VA 22904-4745, USA Journal Metallurgical and Materials Transactions A Online ISSN 1543-1940 Print ISSN 1073-5623

Description:    Laboratory experiments are widely used to study how populations in nature might respond to various biological interactions, but the relevance of experiments in artificial venues is not known. We compiled mortality and growth data from 424 anuran populations carried out under laboratory, mesocosm, field enclosure, and field settings to determine if major differences exist amongst experimental venues and how this might influence experimental responses of tadpoles amongst venues. Our results show that there are fundamental differences in survival amongst venues, with the highest mortality occurring in field populations and the lowest in laboratory populations. Separation of mesocosm and field enclosure data based on the possibility of predatory interactions indicates that predation is an important factor leading to increased mortality in natural populations. Comparisons of size distributions across venues (although size data were limited for field populations) suggest that variation in tadpole size is low in natural populations compared to populations in artificial venues. We infer from this that mortality has a homogenizing effect on size in nature, resulting in natural populations that are not a random sample of hatched individuals. This finding suggests that populations reared under controlled laboratory conditions in the absence of predation (and other selective pressures) may not be representative of natural populations. Content Type Journal Article Category Concepts, Reviews and Synthesis Pages 1-8 DOI 10.1007/s00442-012-2260-9 Authors Steven D. Melvin, Department of Biology and Canadian Rivers Institute, University of New Brunswick, Saint John, NB E2L 4L5, Canada Jeff E. Houlahan, Department of Biology and Canadian Rivers Institute, University of New Brunswick, Saint John, NB E2L 4L5, Canada Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Differences among exotic species can be as large as differences between native and exotic species. Typically, however, only the distinction between native and exotic is made when predicting responses in a community. In this paper, I examine the response of plant species to experimental disturbance and exclusion of invasive European rabbits ( Oryctolagus cuniculus ) in a grassland community with exotic plants originating from five continents. I explore group responses based on native status, shared native range with rabbits, having a congener from the native range of rabbits, life-history (e.g., annual), and life-form (e.g., grass). Individual species responses to rabbits were idiosyncratic, but group responses were predicted by continent of origin, not native status. Native status did predict response to disturbance with almost uniform responses within groups. Exotic species, regardless of origin, were positively affected by disturbance. Native species, in contrast, were negatively affected by disturbance. These results suggest that grouping plant species by native status is valid for questions of disturbance, but when analyzing outcomes of interactions, factors other than native status, such as shared evolutionary history, should be considered. Content Type Journal Article Category Community ecology - Original research Pages 1-7 DOI 10.1007/s00442-012-2265-4 Authors Lisa Castillo Nelis, Committee on Evolutionary Biology, University of Chicago, 1101 E. 57th Street, Chicago, IL 60637, USA Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Plants in nature are often attacked by multiple enemies whose effect on the plant cannot always be predicted based on the outcome of individual attacks. We investigated how two invasive herbivores, the hemlock woolly adelgid ( Adelges tsugae ) (HWA) and the elongate hemlock scale ( Fiorinia externa ) (EHS), alter host plant quality (measured as amino acid concentration and composition) when feeding individually or jointly on eastern hemlock ( Tsuga canadensis ), an important long-lived forest tree that is in severe decline. The joint herbivore treatments included both simultaneous and sequential infestations by the two herbivores. We expected resource depletion over time, particularly in response to feeding by HWA. In contrast, HWA dramatically increased the concentration and altered the composition of individual free amino acids. Compared to control trees, HWA increased total amino acid concentration by 330% after 1 year of infestation. Conversely, EHS had a negligible effect when feeding individually. Interestingly, there was a marginally significant HWA × EHS interaction that suggests the potential for EHS presence to reduce the impact of HWA on foliage quality when the two species co-occur. We suggest indirect effects of water stress as a possible physiological mechanism for our results. Understanding how species interactions change the physiology of a shared host is crucial to making more accurate predictions about host mortality and subsequent changes in affected communities and ecosystems, and to help design appropriate management plans. Content Type Journal Article Category Plant-animal interactions - Original research Pages 1-10 DOI 10.1007/s00442-012-2267-2 Authors Sara Gómez, Department of Biological Sciences, University of Rhode Island, Kingston, RI 02881, USA Colin M. Orians, Department of Biology, Tufts University, Medford, MA 02155, USA Evan L. Preisser, Department of Biological Sciences, University of Rhode Island, Kingston, RI 02881, USA Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    The relationships between landscape intensification, the abundance and diversity of pollinating insects, and their contributions to crop yield, quality, and market value are poorly studied, despite observed declines in wild and domesticated pollinators. Abundance and species richness of pollinating insects were estimated in ten fields of spring oilseed rape, Brassica napus var. SW Stratos™, located along a gradient of landscape compositions ranging from simple landscapes dominated by arable land to heterogeneous landscapes with extensive cover of semi-natural habitats. In each field, we assessed the contribution of wind and insect pollination to seed yield, seed quality (individual seed weight and oil and chlorophyll contents), and market value in a block experiment with four replicates and two treatments: (1) all flowers were accessible to insects, self and wind pollination, and (2) flowers enclosed in tulle net bags (mesh: 1 × 1 mm) were accessible only to wind and self pollination. Complex landscapes enhanced the overall abundance of wild insects as well as the abundance and species richness of hoverflies. This did not translate to a higher yield, probably due to consistent pollination by honey bees across all fields. However, the pollination experiment showed that insects increased seed weight per plant by 18% and market value by 20%. Seed quality was enhanced by insect pollination, rendering heavier seeds as well as higher oil and lower chlorophyll contents, clearly showing that insect pollination is required to reach high seed yield and quality in oilseed rape. Our study demonstrates considerable and previously underestimated contributions from pollinating insects to both the yield and the market value of oilseed rape. Content Type Journal Article Category Plant-animal interactions - Original research Pages 1-8 DOI 10.1007/s00442-012-2271-6 Authors Riccardo Bommarco, Department of Ecology, Swedish University of Agricultural Sciences, 75007 Uppsala, Sweden Lorenzo Marini, Department of Ecology, Swedish University of Agricultural Sciences, 75007 Uppsala, Sweden Bernard E. Vaissière, INRA, UR406 Abeilles & Environnement, 84914 Avignon Cedex 9, France Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Welding between AZ31B Mg alloy and Q235 mild steel was examined in this study. The effects of welding parameters were first investigated on the penetration depth into the steel and the shear strength of the joints. The optimum parameters and the maximum shear strength were obtained. Based on these parameters, alloying elements in the form of interlayers were added into the joints, and the shear strength was improved as high as 98 pct of the AZ31B Mg alloy. Microstructures of the joints were inspected with a scanning electron microscope and an electron probe micro-analyzer. Two bonding modes were proposed, and their effects on the joint shear strength were discussed. It is suggested that the bonding changed from nonmetallurgical to “semimetallurgical” mode with the addition of the interlayers, which contributed to the enhancement of the shear strength. Micro-hardness profiles were measured in the fusion zone of the joints, and their influence on the joint strength was also discussed. Intermediate phases that distributed uniformly in the fusion zone strengthened the microstructures, and thus, the shear strength was elevated. An empirical trend for Cu and Ni interlayer selection was proposed. Content Type Journal Article Pages 1-13 DOI 10.1007/s11661-011-1071-7 Authors Liming Liu, Key Laboratory of Liaoning Advanced Welding and Joining Technology, School of Materials Science and Engineering, Dalian University of Technology, Dalian, 116024 P.R. China Xiaodong Qi, Key Laboratory of Liaoning Advanced Welding and Joining Technology, School of Materials Science and Engineering, Dalian University of Technology, Dalian, 116024 P.R. China Zhaodong Zhang, Key Laboratory of Liaoning Advanced Welding and Joining Technology, School of Materials Science and Engineering, Dalian University of Technology, Dalian, 116024 P.R. China Journal Metallurgical and Materials Transactions A Online ISSN 1543-1940 Print ISSN 1073-5623

Description:    First-principles method was performed to predict the effect of Ti addition on thickness and adhesion of 55 pct Al-Zn-1.6 pct Si coating. The results of optimized geometric configurations, total energy, and charge distributions for the Ti substitution in Fe2Al5 and FeAl3 phases indicated Ti will grab electronic charges from Al atoms, form bonds with neighboring Al, which will reduce the growth of Fe-Al intermetallic layers, and finally enhance the adhesion of the coating/substrate. Furthermore, experiments were performed to validate the prediction results of first-principles successfully. Content Type Journal Article Pages 1-6 DOI 10.1007/s11661-011-1037-9 Authors Guangxin Wu, School of Materials Science and Technology, Shanghai University, Shanghai, 200072 P.R. China Jieyu Zhang, School of Materials Science and Technology, Shanghai University, Shanghai, 200072 P.R. China Yuling Ren, Cold Rolling Plant, Baosteel Branch, Baoshan Iron & Steel Co. Ltd., Shanghai, 200941 P.R. China Guoyang Li, Cold Rolling Plant, Baosteel Branch, Baoshan Iron & Steel Co. Ltd., Shanghai, 200941 P.R. China Xiaochun Wu, School of Materials Science and Technology, Shanghai University, Shanghai, 200072 P.R. China Qian Li, School of Materials Science and Technology, Shanghai University, Shanghai, 200072 P.R. China Kuochih Chou, School of Materials Science and Technology, Shanghai University, Shanghai, 200072 P.R. China Journal Metallurgical and Materials Transactions A Online ISSN 1543-1940 Print ISSN 1073-5623

Description:    Quick preheating treatment of the Al-Ti-C pellets and high-intensity ultrasonic vibration are introduced in the fabrication of in-situ TiC p /Mg composites. Al-Ti-C pellets are preheated for about 130 seconds in the furnace at 1023 K (750 °C), in which magnesium is melted as well. In this process, plenty of heat can be accumulated due to the reactive diffusion between liquid aluminum and solid titanium in Al-Ti-C, and a small amount of Al 3 Ti phase is formed as well. After adding the preheated Al-Ti-C into the molten magnesium, thermal explosion takes place in a few seconds. In the meantime, high-intensity ultrasonic vibration is applied into the melt to disperse in-situ formed TiC particles into the matrix and degas the melt as well. Microstructural characterization indicates that in-situ formed TiC particles are spherical in morphology and smaller than 2  μ m in size. Furthermore, a homogeneous microstructure with low porosity of the magnesium composite is obtained due to the effect of ultrasonic vibration. A novel approach using the quick preheating treatment technique and high-intensity ultrasonic vibration to synthesize in-situ TiC p /Mg composites is proposed in our research. Content Type Journal Article Pages 1-9 DOI 10.1007/s11661-011-1041-0 Authors Z. W. Liu, School of Materials Science and Engineering, Shanghai Jiaotong University, Shanghai, 200240 P.R. China M. Rakita, Department of Mechanical Engineering Technology, Purdue University, West Lafayette, IN 47906, USA Q. Han, Department of Mechanical Engineering Technology, Purdue University, West Lafayette, IN 47906, USA J. G. Li, School of Materials Science and Engineering, Shanghai Jiaotong University, Shanghai, 200240 P.R. China Journal Metallurgical and Materials Transactions A Online ISSN 1543-1940 Print ISSN 1073-5623

Description:    Mg-10Gd-3Y-0.5Zr (wt pct) casting was subjected to friction stir processing (FSP) at a constant rotation rate of 800 rpm and varied travel speeds of 25, 50, and 100 mm/minute. FSP resulted in the generation of fine-grained microstructure and fundamental dissolution of coarse Mg 5 (Gd,Y) phase at the grain boundaries, thereby enhancing the tensile properties significantly at both room and elevated temperatures. The grain size of the FSP samples decreased with the increasing travel speed, whereas the microstructure heterogeneity with the banded structure (onion rings) became evident at a higher travel speed. Tensile elongation of the FSP samples increased as the travel speed increased, whereas the highest strengths were obtained at the medium travel speed of 50 mm/minute. Higher strengths and greater elongations were observed for the FSP samples in the transverse direction (TD) than in the longitudinal direction (LD). After post-FSP aging, the strengths of the FSP samples were increased significantly with the TD and LD exhibiting the same strengths; however, the elongation was decreased remarkably with the TD having higher elongation than the LD. A variation of the tensile properties was discussed in detail based on the microstructure heterogeneity and fracture surfaces. Content Type Journal Article Pages 1-16 DOI 10.1007/s11661-011-1076-2 Authors Q. Yang, Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, 110016 P.R. China B. L. Xiao, Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, 110016 P.R. China Z. Y. Ma, Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, 110016 P.R. China Journal Metallurgical and Materials Transactions A Online ISSN 1543-1940 Print ISSN 1073-5623

Description:    The jerky and smooth flow curves in high-manganese twinning induced plasticity (TWIP) steels were investigated by comparing Fe-Mn-C and Fe-Mn-Al-C systems. The pronounced serrations on the flow curves of Fe-Mn-C TWIP steel, produced during tensile testing at 300 K (27 °C) and 373 K (100 °C), were shown to be the result of localized high-temperature Portevin Le-Chatelier (PLC) bands moving across the gage length throughout the deformation. The speed of the PLC bands and their temperature effects were found to be strongly dependent on the applied strain rate, which was controlled by adjusting the cross-head speed of the tensile testing machine. The localized temperature-dependent stacking fault energy (SFE) variations resulting from the PLC effect and adiabatic heating were analyzed and compared for both slow and fast deformation rates. The instabilities in the measured logarithmic strain values caused by jerky flow could cause the local strain rate to deviate systematically from the targeted (applied) strain rate. These instabilities are better observed by calculating the instantaneous strain rate (ISR) values for each instant of deformation along the entire gage length. Finally, a new type of diagram was developed by plotting the true stress against the ISR values. From the diagram, the onset of different mechanisms, such as deformation twinning, nonpronounced, and pronounced serrations, could be marked precisely. Content Type Journal Article Pages 1-19 DOI 10.1007/s11661-011-1070-8 Authors A. Saeed-Akbari, Department of Ferrous Metallurgy, RWTH Aachen University, 52072 Aachen, Germany A. K. Mishra, Department of Metallurgical & Materials Engineering, Indian Institute of Technology, Kharagpur, 721302 India J. Mayer, Central Facility for Electron Microscopy, Aachen, Germany W. Bleck, Department of Ferrous Metallurgy, RWTH Aachen University, 52072 Aachen, Germany Journal Metallurgical and Materials Transactions A Online ISSN 1543-1940 Print ISSN 1073-5623

Description:    The effect of preoxidation on the thermal shock of air plasma sprayed thermal barrier coatings (TBCs) was completely investigated in a combustion gas environment by burning jet fuel with high speed air. Results show that with increasing cycles, the as-oxidized TBCs lost more weight and enlarged larger spallation area than the as-sprayed ones. Thermally grown oxide (TGO) growth and thermal mismatch stress were proven to play critical roles on the as-oxidized TBC failure. Two types of significant cracks were identified: the type I crack was vertical to the TGO interface and the type II crack was parallel to the TGO interface. The former accelerated the TGO growth to develop the latter as long as the oxidizing gas continuously diffused inward and then oxidized the more bond coat (BC). The preoxidation treatment directly increased the TGO thickness, formed the parallel cracks earlier in the TGO during the thermal shocks, and eventually resulted in the worse thermal shock resistance. Content Type Journal Article Pages 1-10 DOI 10.1007/s11661-011-1055-7 Authors Hui Mei, National Key Laboratory of Thermostructure Composite Materials, School of Materials Science, Northwestern Polytechnical University, Xi’an, Shaanxi 710072, P.R. China Journal Metallurgical and Materials Transactions A Online ISSN 1543-1940 Print ISSN 1073-5623

Description:    The broad spectrum of anthropogenic pressures on many of the world’s coastal bays and estuaries rarely act in isolation, yet few studies have directly addressed the interactive effects of multiple pressures. Port Phillip Bay in southeastern Australia is a semi-enclosed bay in which nutrient management is a major concern. In recent years it has been heavily invaded by marine pests. We manipulated the density of one such invader, the European fanworm Sabella spallanzanii , and showed that it causes changes in the composition of macrofauna in the surrounding sediments, provides habitat for epibiota (both fauna and flora) on Sabella tubes, and reduces the biomass of microphytobenthos on the surrounding sediments. Of greatest concern, however, was the indirect impact on nutrient cycling. We suggest that the impacts on nutrient cycling are largely due to the feeding of Sabella and the epifauna on its tubes, capturing organic N before it reaches the sediment, excreting it back up into the water column as NH 4 , thereby bypassing sedimentary processes such as denitrification. Most notably, the efficiency of denitrification, the key ecosystem process that permanently removes N from the system, fell by 37–53 % in the presence of Sabella . Importantly though, this study also demonstrated significant spatial variability in fauna, geochemistry and the magnitude of Sabella effects. Given that the effect of Sabella is also likely to vary in time and with changes in density, all of these sources of variability need to be considered when incorporating the effects of Sabella in nutrient management strategies. Content Type Journal Article Category Ecosystem ecology - Original research Pages 1-14 DOI 10.1007/s00442-012-2497-3 Authors D. Jeff Ross, Department of Zoology, University of Melbourne, Melbourne, VIC 3010, Australia Andy R. Longmore, Department of Primary Industries, Fisheries Research Branch, Bellarine Highway, Queenscliff, VIC 3225, Australia Michael J. Keough, Department of Zoology, University of Melbourne, Melbourne, VIC 3010, Australia Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Little is known about intraspecific variation in fitness performance in response to thermal stress among natural populations and how this relates to evolutionary aspects of species ecology. In this study, population growth rate (PGR; a composite fitness measure) varied among five natural Chironomus riparius populations sampled across a climatic gradient when subjected to three temperature treatments reflecting the typical range of summer habitat temperatures (20, 24 and 28 °C). The variation could be explained by a complex model including effects of genetic drift, genetic diversity and adaptation to average temperature during the warmest month, in addition to experimental temperature. All populations suffered a decrease in PGR from 20 to 28 °C and ΔPGR was significantly correlated with the respective average habitat temperature in the warmest month—populations from warmer areas showing lower ΔPGR. This implies that long-term exposure to higher temperatures in the warmest month (the key reproductive period for C. riparius ) is likely to be a key selective force influencing fitness at higher temperatures. A comparison of phenotypic divergence and neutral genetic differentiation revealed that one phenotypic trait—the number of fertile egg masses per female—appeared to be under positive selection in some populations. Our findings support a role for response to temperature selection along a climatic gradient and suggest population history is a key determinant of intraspecific fitness variation. We stress the importance of integrating different types of data (climatic, experimental, genetic) in order to understand the effects of global climate change on biodiversity. Content Type Journal Article Category Global change ecology - Original research Pages 1-10 DOI 10.1007/s00442-012-2517-3 Authors Sabrina Nemec, Conservation Genetics Section, Senckenberg Gesellschaft für Naturforschung, Clamecystrasse 12, 63571 Gelnhausen, Germany Simit Patel, Molecular Ecology Group, Biodiversity and Climate Research Centre (BiK-F), Senckenberg Gesellschaft für Naturforschung and Goethe University, 60325 Frankfurt am Main, Germany Carsten Nowak, Conservation Genetics Section, Senckenberg Gesellschaft für Naturforschung, Clamecystrasse 12, 63571 Gelnhausen, Germany Markus Pfenninger, Molecular Ecology Group, Biodiversity and Climate Research Centre (BiK-F), Senckenberg Gesellschaft für Naturforschung and Goethe University, 60325 Frankfurt am Main, Germany Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Bayesian neural networks have been developed, which relate composition, microstructure, and tensile properties of the alloy TIMETAL 6-4 (nominal composition: Ti-6Al-4V (wt pct) after thermomechanical processing (TMP) in the two-phase ( α  +  β )-phase field. The developed networks are able to make interpolative predictions of properties within the ranges of composition and microstructural features that are in the population of the database used for training and testing of the networks. In addition, the neural networks have been used to conduct virtual experiments which permit the functional dependencies of properties on composition and microstructural features to be determined. In this way, it is shown that in the microstructural condition resulting from TMP in the two-phase ( α  +  β ) phase field, the most significant contribution to strength is from solid solution strengthening, with microstructural features apparently influencing the balance of a number of properties. Content Type Journal Article Pages 1-13 DOI 10.1007/s11661-012-1498-5 Authors Peter C. Collins, Department of Materials Science and Engineering, The Ohio State University, Columbus, OH 43210, USA Santhosh Koduri, Department of Materials Science and Engineering, The Ohio State University, Columbus, OH 43210, USA Brian Welk, Department of Materials Science and Engineering, The Ohio State University, Columbus, OH 43210, USA Jaimie Tiley, Materials and Manufacturing Directorate, Air Force Research Laboratory, Wright Patterson Air Force Base, Dayton, OH, USA Hamish L. Fraser, Department of Materials Science and Engineering, The Ohio State University, Columbus, OH 43210, USA Journal Metallurgical and Materials Transactions A Online ISSN 1543-1940 Print ISSN 1073-5623

Description:    Nanocrystalline iron and oxide dispersion-strengthened (ODS) iron powders (Fe, Fe-Y 2 O 3 , and Fe-Y 2 O 3 -Ti) were prepared by mechanical milling for periods ranging from 1 to 40 hours. The as-milled powders were examined for changes in their particle sizes, crystallite sizes, hardness values, and phases present as a function of milling time. Both the particle and the crystallite sizes of all the three compositions decreased with milling time, while the hardness values of all the three powders increased with milling time because of the crystallite size refinement. At the same crystallite size, the hardness values of Fe-Y 2 O 3 and Fe-Y 2 O 3 -Ti powders were higher than that of the Fe powders. Though, the presence of 40 nm Y 2 O 3 could be established for 2-hour milling, such particles were not resolvable in 40-hour-milled powders. However, SAD patterns confirmed the presence of complex oxide dispersoids in the Fe-Y 2 O 3 and Fe-Y 2 O 3 -Ti powders. The variation of hardness value with the crystallite size and as a function of the milling time can be rationalized on the basis of Hall–Petch crystallite size strengthening in combination with dispersion strengthening (in Fe-Y 2 O 3 - and Fe-Y 2 O 3 -Ti-milled powders) due to dispersoids. The observed double-positive slopes in the Hall–Petch relationship can be explained in terms of an increase in misorientation angle between the crystallites with increasing milling time due to the crystallite rotation driven by disclination dipoles. Content Type Journal Article Pages 1-10 DOI 10.1007/s11661-012-1494-9 Authors R. Vijay, International Advanced Research Centre for Powder Metallurgy & New Materials (ARCI), Balapur, Hyderabad 500 005, India M. Nagini, International Advanced Research Centre for Powder Metallurgy & New Materials (ARCI), Balapur, Hyderabad 500 005, India J. Joardar, International Advanced Research Centre for Powder Metallurgy & New Materials (ARCI), Balapur, Hyderabad 500 005, India M. Ramakrishna, International Advanced Research Centre for Powder Metallurgy & New Materials (ARCI), Balapur, Hyderabad 500 005, India A. V. Reddy, International Advanced Research Centre for Powder Metallurgy & New Materials (ARCI), Balapur, Hyderabad 500 005, India G. Sundararajan, International Advanced Research Centre for Powder Metallurgy & New Materials (ARCI), Balapur, Hyderabad 500 005, India Journal Metallurgical and Materials Transactions A Online ISSN 1543-1940 Print ISSN 1073-5623

Description:    The current trend toward producing lighter vehicles in the automotive industry is driven by the need to conform to the new exhaust emission control regulations. This objective presents a challenge to steel manufacturers. The difficulty lies in designing new alloys with an optimum strength/formability/cost balance for the various components. Here, the key to success lies in controlling the steel microstructure and especially the phase transformations at the smallest possible scale. Among the different alloying elements, light elements such as carbon and boron are of prime importance due to their major effects on the kinetics of phase transformations. Characterization tools combining high spatial and analytical resolution such as secondary ion mass spectrometry (SIMS) and field emission gun-transmission electron microscopy (TEM) were used. In this article, the examples presented are as follows. (1) Boron segregation and precipitation effects to control hardenability in martensitic steels. (2) Local carbon distribution in advanced high-strength steels, with a specific emphasis on martensite tempering. Links have been established between the boron and carbon distribution and the formability. Content Type Journal Article Pages 1-10 DOI 10.1007/s11661-012-1218-1 Authors Josée Drillet, ArcelorMittal Maizières R&D, BP30320, 57283 Maizières-les-Metz Cedex, France Nathalie Valle, SAM Department, CRP-Gabriel Lippmann, 41 rue du Brill, 4422 Belvaux, Luxembourg Thierry Iung, ArcelorMittal Maizières R&D, BP30320, 57283 Maizières-les-Metz Cedex, France Journal Metallurgical and Materials Transactions A Online ISSN 1543-1940 Print ISSN 1073-5623

Description:    A methodology for determining the preferred site occupancy of various alloying elements within ordered γ′ precipitates was developed and applied to Rene88 samples. The method utilized atom probe tomography and X-ray diffraction techniques with controlled monochromated synchrotron beams to determine element positions. Samples were solutionized at 1423 K (1150 °C) for 30 minutes and cooled at 24 K/min with subsequent aging at 1033 K (760 °C). The synchrotron X-ray diffraction results indicate that niobium prefers to reside on the aluminum sublattice site of the γ′ phase. Additionally, the results indicate that chromium prefers the nickel sublattice sites, while cobalt is likely to occupy both the aluminum and nickel sublattice sites. The X-ray results on the chromium occupancy disagree with atom probe results from the same alloy that indicate that chromium prefers the aluminum sublattice sites. Content Type Journal Article Category Symposium: Neutron and X-Ray Studies of Advanced Materials V Pages 1-8 DOI 10.1007/s11661-012-1456-2 Authors Jaimie S. Tiley, Air Force Research Laboratory, Wright Patterson AFB, OH 45433, USA O. Senkov, Air Force Research Laboratory, Wright Patterson AFB, OH 45433, USA G. Viswanathan, Air Force Research Laboratory, Wright Patterson AFB, OH 45433, USA S. Nag, Department of Materials Science, Center for Advanced Research and Technology, University of North Texas, Denton, TX 76203, USA J. Hwang, Institute of Advanced Composite Materials, Korea Institute of Science and Technology, Jeonbuk, 565-902 Korea R. Banerjee, Department of Materials Science, Center for Advanced Research and Technology, University of North Texas, Denton, TX 76203, USA Journal Metallurgical and Materials Transactions A Online ISSN 1543-1940 Print ISSN 1073-5623

Description:    By using high-energy synchrotron X-ray and neutron scattering, the local structure of a ternary high-entropy alloy Zr 1/3 Nb 1/3 Hf 1/3 is characterized by means of pair distribution function (PDF) analysis. Results show that this alloy is a body center cubic (b.c.c.) phase in both bulk sample and in a thin film ~1.5  µ m thick. The PDFs obtained from X-ray diffraction and neutron diffraction agree well with each other. The measured PDFs differ from the calculated PDF, particularly in the peak shape of the first two peaks, indicating local lattice distortion due to different atomic sizes in the solid solution. Content Type Journal Article Category Symposium: Bulk Metallic Glasses IX Pages 1-4 DOI 10.1007/s11661-012-1474-0 Authors Wei Guo, Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN 37996, USA Wojciech Dmowski, Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN 37996, USA Ji-Yong Noh, Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN 37996, USA Philip Rack, Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN 37996, USA Peter K. Liaw, Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN 37996, USA Takeshi Egami, Joint Institute for Neutron Sciences, Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN 37996, USA Journal Metallurgical and Materials Transactions A Online ISSN 1543-1940 Print ISSN 1073-5623

Description:    In rapidly evolving powder injection molding technology, the wide prevalence of various microstructures demands the powders of smaller particle sizes. The effects of particle size on the sintering behavior are critical to not only shape retention of microstructure but also its mechanical properties. This study investigates the effects of three different particle sizes on the sintering behavior of the 316L stainless steel (STS316L) samples, prepared by powder injection molding, via the dilatometry experiments. For this purpose, the STS316L powders of three different mean particle sizes, i.e. , 2.97, 4.16, and 8.04  μ m, were produced for STS316L. The samples for the dilatometry test were prepared through powder-binder mixing, injection molding, and solvent and thermal debinding. Dilatometry experiments were carried out with the samples in a H 2 atmosphere at three different heating rates of 3, 6, and 10 K/min. The shrinkage data obtained by dilatometry experiments was collected and analyzed to help understand the densification and the sintering behaviors in terms of particles size and heating rate. The master sintering curve (MSC) model was used to quantify the effects of particle sizes. In addition, we investigated the microstructure evolutions in terms of particles sizes. Content Type Journal Article Pages 1-11 DOI 10.1007/s11661-012-1477-x Authors Dong Yong Park, Department of Mechanical Engineering, and Division of Advanced Nuclear Engineering, POSTECH, Pohang, Gyungbuk 790-784, Korea Shi W. Lee, Department of Industrial Engineering, Pusan National University, Busan, 609-735 Korea Seong Jin Park, Department of Mechanical Engineering, and Division of Advanced Nuclear Engineering, POSTECH, Pohang, Gyungbuk 790-784, Korea Young-Sam Kwon, CetaTech, Inc., Sacheon, Gyungnam 664-950, Korea Isamu Otsuka, MP Development & Engineering Department, Epson Atmix Corporation, Hachinohe, Aomori 039-1161, Japan Journal Metallurgical and Materials Transactions A Online ISSN 1543-1940 Print ISSN 1073-5623

Description:    The microstructure and properties of a precipitation-hardenable Ni-48Ti-25Pd (at. pct) shape memory alloy have been investigated as a function of various aging conditions. Both the hardness and martensitic transformation temperatures increased with increasing aging time up to 100 hours at 673 K (400 °C), while no discernable differences were observed after heat treatment at 823 K (550 °C), except for a slight decrease in hardness. For aging at 673 K (400 °C), these effects were attributed to the formation of nano-scale precipitates, while precipitation was absent in the 823 K (550 °C) heat-treated specimens. The precipitation-strengthened alloy exhibited stable pseudoelastic behavior and load-biased-shape memory response with little or no residual strains. The precipitates had a monoclinic base-centered structure, which is the same structure as the P-phase recently reported in Ni(Pt)-rich NiTiPt alloys. 3D atom probe analysis revealed that the precipitates were slightly enriched in Ni and deficient in Pd and Ti as compared with the bulk alloy. The increase in martensitic transformation temperatures and the superior dimensional stability during shape memory and pseudoelastic testing are attributed to the fine precipitate phase and its effect on matrix chemistry, local stress state because of the coherent interface, and the ability to effectively strengthen the alloy against slip. Content Type Journal Article Pages 1-13 DOI 10.1007/s11661-012-1481-1 Authors Taisuke T. Sasaki, Department of Metallurgical and Materials Engineering, The University of Alabama, Tuscaloosa, AL, USA B. Chad Hornbuckle, Department of Metallurgical and Materials Engineering, The University of Alabama, Tuscaloosa, AL, USA Ronald D. Noebe, Structures and Materials Division, NASA Glenn Research Center, Cleveland, OH, USA Glen S. Bigelow, Structures and Materials Division, NASA Glenn Research Center, Cleveland, OH, USA Mark L. Weaver, Department of Metallurgical and Materials Engineering, The University of Alabama, Tuscaloosa, AL, USA Gregory B. Thompson, Department of Metallurgical and Materials Engineering, The University of Alabama, Tuscaloosa, AL, USA Journal Metallurgical and Materials Transactions A Online ISSN 1543-1940 Print ISSN 1073-5623

Description:    This article compares chromium evaporation characteristics of chromia- and alumina-forming alloys at high temperatures [1123 K and 1223 K (800 °C to 950 °C)] in humid air (3 and 12 pct H 2 O) and presents a mechanistic understanding of variation in chromium evaporation on the basis of their oxide scale morphologies. For this study, an alloy from each of the distinct chromia-forming, alumina-forming, and chromia-alumina transition characteristics was selected ( i.e. , an alumina-forming alloy (Aluchrom YHf), a chromia-forming alloy (AISI 310S-austentic stainless steel), and an alloy that undergoes transition from chromia to alumina formation (Nicrofer6025 HT)). For generating baseline chromium evaporation data, pure chromium oxide was also tested. The chromium evaporation rate decreased in the order pure chromium oxide 〉 AISI 310S 〉 Nicrofer6025 HT 〉 Aluchrom YHf. Surface morphologies, cross sections, and chemical characteristics of oxide scales were examined by scanning electron microscopy and energy dispersive X-ray spectroscopy and focused ion beam. The variation in chromium evaporation of different alloys is explained on the basis of physical and chemical characteristics of the oxide scales. Content Type Journal Article Pages 1-14 DOI 10.1007/s11661-012-1492-y Authors Le Ge, Department of Chemical, Materials & Biomolecular Engineering, Center for Clean Energy Engineering, University of Connecticut, Storrs, CT 06269, USA Atul Verma, Department of Chemical, Materials & Biomolecular Engineering, Center for Clean Energy Engineering, University of Connecticut, Storrs, CT 06269, USA Richard Goettler, Rolls-Royce Fuel Cell Systems (US) Inc., North Canton, OH 44720, USA David Lovett, Rolls-Royce Fuel Cell Systems (US) Inc., North Canton, OH 44720, USA R. K. Singh Raman, Departments of Mechanical & Aerospace Engineering, and Chemical Engineering, Monash University, Melbourne, VIC 3800, Australia Prabhakar Singh, Department of Chemical, Materials & Biomolecular Engineering, Center for Clean Energy Engineering, University of Connecticut, Storrs, CT 06269, USA Journal Metallurgical and Materials Transactions A Online ISSN 1543-1940 Print ISSN 1073-5623

Description:    In this study, the accumulative roll bonding and folding (ARBF) process was used for manufacturing nanostructured aluminum/copper multilayered composites. Textural evolution during the ARBF process of composites was evaluated using X-ray diffraction. Microstructural observation of some samples was evaluated by scanning electron microscopy and transmission electron microscopy. The ARBF process induced formation of a strong preferred orientation along the β-fiber and also to the pronounced copper texture component. In the aluminum side, occurrence of dynamic recovery reduced the intensity of the β-fiber rolling texture due to change in dislocation structure and decrease in the degree of strain hardening. On the other hand, occurrence of discontinuous dynamic recrystallization at the third and fourth ARBF cycles led to decreasing the intensity of fibers and texture components in the copper side. The average grain sizes of the final sample for the copper and aluminum sides were ~50 and ~200 nm, respectively. Content Type Journal Article Pages 1-12 DOI 10.1007/s11661-012-1503-z Authors Mohammad Reza Toroghinejad, Department of Materials Engineering, Isfahan University of Technology, 84156-83111 Isfahan, Iran Roohollah Jamaati, Department of Materials Engineering, Isfahan University of Technology, 84156-83111 Isfahan, Iran Majid Hoseini, Department of Mining, Metals and Materials Engineering, McGill University, Montreal, QC H3A 2B2, Canada Jerzy A. Szpunar, Department of Mechanical Engineering, University of Saskatchewan, Saskatoon, SK S7N 5A9, Canada Jan Dutkiewicz, Institute of Metallurgy and Materials Science of the Polish Academy of Sciences, ul. Reymonta 25, 30-059 Krakow, Poland Journal Metallurgical and Materials Transactions A Online ISSN 1543-1940 Print ISSN 1073-5623

Description:    Al- Cu alloys (such as A206) offer high strength and high fracture toughness at both room and elevated temperatures. However, their widespread applications are limited because of their high susceptibility to hot tearing. This article presents a nanotechnology approach to enhance hot-tearing resistance for A206. Specifically, γ-Al 2 O 3  nanoparticles were used, and their effects on the hot-tearing resistance of the as-cast Al-4.5Cu alloy (A206) were investigated. While it is well known that grain refinement can improve the hot-tearing resistance of cast Al alloys, the current study demonstrated that nanoparticles can be much more effective in the case of A206. The hot-tearing susceptibilities (HTSs) of A206 alloy and its Al 2 O 3  nanocomposite were evaluated by constrained rod casting (CRC) with a steel mold. Monolithic A206 and M206 (the Ti-free version of A206) alloys with the B contents of 20, 40, and 300 ppm from an Al-5Ti-1B master alloy addition were also cast under the same conditions for comparison. The results showed that with an addition of 1 wt pct γ-Al 2 O 3  nanoparticles, the extent of hot tearing in A206 alloys was markedly reduced to nearly that of A356, an Al-Si alloy highly resistant to hot tearing. As compared with grain-refined A206 or M206, the hot-tearing resistance of the nanocomposites was significantly better, even though the grain size was not reduced as much. Microstructural analysis suggested that γ-Al 2 O 3  nanoparticles modified the solidification microstructure of the eutectic of θ-Al 2 Cu and α-Al, as well as refined primary grains, resulting in the enhancement of the hot-tearing resistance of A206 to a level similar to that of A356 alloy. Content Type Journal Article Pages 1-11 DOI 10.1007/s11661-012-1531-8 Authors Hongseok Choi, Department of Mechanical Engineering, University of Wisconsin-Madison, 1035 Mechanical Engineering Bldg., 1513 University Avenue, Madison, WI 53706, USA Woo-hyun Cho, Department of Mechanical Engineering, University of Wisconsin-Madison, 1035 Mechanical Engineering Bldg., 1513 University Avenue, Madison, WI 53706, USA Hiromi Konishi, Departments of Geoscience and Mechanical Engineering, University of Wisconsin-Madison, Madison, WI 53706, USA Sindo Kou, Department of Materials Science and Engineering, University of Wisconsin-Madison, 1509 University Avenue, Madison, WI 53706, USA Xiaochun Li, Department of Mechanical Engineering, University of Wisconsin-Madison, 1035 Mechanical Engineering Bldg., 1513 University Avenue, Madison, WI 53706, USA Journal Metallurgical and Materials Transactions A Online ISSN 1543-1940 Print ISSN 1073-5623

Description:    The kinetics of the γ′ phase dissolution have been studied at 1473 K and 1523 K (1200 °C and 1250 °C) for CMSX-4 ® alloy. Interrupted creep tests at 1323 K (1050 °C) and pure thermal aging at 1373 K (1100 °C) have been used to vary the initial γ′ morphology. Subsequent dissolution studies were conducted with or without an applied load. Differences in γ′ dissolution kinetics were observed between the dendrite cores and the interdendritic regions, resulting from the chemical microsegregations remaining after the standard heat treatments. It is shown that the initial γ′ morphology, the relaxation of the coherency stresses and the accumulated plastic strain are critical parameters controlling the dissolution kinetics. An increase of the accumulated plastic strain leads to an increase of the dissolution kinetics, whatever the location in the dendritic structure. In addition, once a given accumulated creep strain is reached prior to the dissolution tests ( i.e. , a given dislocations density), the dissolution kinetics are the same at 1473 K and 1523 K (1200 °C and 1250 °C). A modified equation of the recently developed Polystar model is proposed to incorporate the role of the accumulated plastic strain on the γ′ dissolution kinetics and to achieve a better predictability of the creep deformation under non-isothermal loading paths. Content Type Journal Article Pages 1-16 DOI 10.1007/s11661-012-1397-9 Authors Rémi Giraud, Turbomeca - SAFRAN Group, Département Matériaux, Procédés et Expertises, 64511 Bordes Cedex, France Zéline Hervier, Turbomeca - SAFRAN Group, Département Matériaux, Procédés et Expertises, 64511 Bordes Cedex, France Jonathan Cormier, Institut Pprime, CNRS—ENSMA—Université de Poitiers, UPR CNRS 3346, Département de Physique et Mécanique des Matériaux, ENSMA—Téléport 2, 1 avenue Clément Ader, BP 40109, 86961 Futuroscope - Chasseneuil Cedex, France Gilles Saint-Martin, Turbomeca - SAFRAN Group, Département Matériaux, Procédés et Expertises, 64511 Bordes Cedex, France Florence Hamon, Institut Pprime, CNRS—ENSMA—Université de Poitiers, UPR CNRS 3346, Département de Physique et Mécanique des Matériaux, ENSMA—Téléport 2, 1 avenue Clément Ader, BP 40109, 86961 Futuroscope - Chasseneuil Cedex, France Xavier Milhet, Institut Pprime, CNRS—ENSMA—Université de Poitiers, UPR CNRS 3346, Département de Physique et Mécanique des Matériaux, ENSMA—Téléport 2, 1 avenue Clément Ader, BP 40109, 86961 Futuroscope - Chasseneuil Cedex, France José Mendez, Institut Pprime, CNRS—ENSMA—Université de Poitiers, UPR CNRS 3346, Département de Physique et Mécanique des Matériaux, ENSMA—Téléport 2, 1 avenue Clément Ader, BP 40109, 86961 Futuroscope - Chasseneuil Cedex, France Journal Metallurgical and Materials Transactions A Online ISSN 1543-1940 Print ISSN 1073-5623

Description:    The effects of processing temperature on the deep-rolling response of three medium carbon bar steels, a quenched and tempered 4140 alloy, a 0.34C, 1.21Mn, 0.66Si nontraditional bainitic alloy, and a 0.36C, 1.37Mn V-microalloyed ferrite plus pearlite steel, was assessed through bending fatigue. The significantly different deformation behaviors of the three alloys were characterized through standard and nonstandard quasi-static and cyclic uniaxial tension and compression tests at room temperature (RT) and in situ at temperatures up to 634 K. Deep rolling, performed at RT and at elevated temperature (HT) in the dynamic strain-aging (DSA) regime, increased measured endurance limits by 51-62 pct (RT) and 96-117 pct (HT) as compared with the baseline condition. The enhanced fatigue performance by RT deep rolling primarily reflected the effects of the introduction of favorable residual stresses. The improved fatigue performance from HT deep rolling was attributed to the enhanced resistance to strain reversal of the material deformed during deep rolling, due to a change in deformation mechanism from dislocation-interstitial interactions in the DSA regime during processing, which inhibited mechanically induced relaxation of residual stress during cyclic loading. Content Type Journal Article Pages 1-16 DOI 10.1007/s11661-012-1371-6 Authors M. D. Richards, Advanced Steel Processing and Products Research Center, Colorado School of Mines, Golden, CO 80401, USA M. E. Burnett, The Timken Co., Canton, OH 44706, USA J. G. Speer, Advanced Steel Processing and Products Research Center, Colorado School of Mines, Golden, CO 80401, USA D. K. Matlock, Advanced Steel Processing and Products Research Center, Colorado School of Mines, Golden, CO 80401, USA Journal Metallurgical and Materials Transactions A Online ISSN 1543-1940 Print ISSN 1073-5623

Description:    The refinement in size and modification in morphology for primary Mg 2 Si depended significantly on Sb contents in Mg-4Si alloys. Adding Sb into melts evidently increased the nucleus numbers of primary Mg 2 Si crystals. Moreover, the preferential growth along á 100 ñ directions in dendritic crystals was restricted greatly due to the Si sites being substituted by Sb in Mg 2 Si lattices, resulting in modified primary Mg 2 Si crystals growing to octahedral morphology surrounded by {111} planes; therefore, the modification process could be called adsorption and poisoning mechanisms. Content Type Journal Article Pages 1-7 DOI 10.1007/s11661-012-1317-z Authors Hui-Yuan Wang, Key Laboratory of Automobile Materials of Ministry of Education & School of Materials Science and Engineering, Jilin University, Nanling Campus, Changchun, 130025 People’s Republic of China Qian Li, Key Laboratory of Automobile Materials of Ministry of Education & School of Materials Science and Engineering, Jilin University, Nanling Campus, Changchun, 130025 People’s Republic of China Bo Liu, Key Laboratory of Automobile Materials of Ministry of Education & School of Materials Science and Engineering, Jilin University, Nanling Campus, Changchun, 130025 People’s Republic of China Nan Zhang, Key Laboratory of Automobile Materials of Ministry of Education & School of Materials Science and Engineering, Jilin University, Nanling Campus, Changchun, 130025 People’s Republic of China Lei Chen, Key Laboratory of Automobile Materials of Ministry of Education & School of Materials Science and Engineering, Jilin University, Nanling Campus, Changchun, 130025 People’s Republic of China Jin-Guo Wang, Key Laboratory of Automobile Materials of Ministry of Education & School of Materials Science and Engineering, Jilin University, Nanling Campus, Changchun, 130025 People’s Republic of China Qi-Chuan Jiang, Key Laboratory of Automobile Materials of Ministry of Education & School of Materials Science and Engineering, Jilin University, Nanling Campus, Changchun, 130025 People’s Republic of China Journal Metallurgical and Materials Transactions A Online ISSN 1543-1940 Print ISSN 1073-5623

Description: Tungsten-copper composites with various copper nano-particles volume fractions were manufactured and examined. Tungsten-copper composites with 20 pct, 25 pct, and 30 pct volume fractions were mechanically mixed and sintered. spark plasma sintering (SPS) method was used for samples preparation at two different sintered temperatures 1273 K and 1373 K (1000 °C and 1100 °C). The effect of copper nano-particles on the bulk density, hardness, the coefficient of thermal expansion (CTE), electrical conductivity, and stress-strain behavior of the produced composites were studied. The hardness was found to decrease with the increase of the copper volume fraction in the composites. Conversely, the CTE and electrical conductivity increases with the increase of the copper volume fraction in the composites. Furthermore, the elastic modulus were extracted from tensile stress-strain behavior were found to increase with the increase of the copper volume fraction in the composites. Finally, the fracture surface roughness was studied using high resolution optical investigations and was noticeably higher with the increase of the copper volume fraction in the composites. Content Type Journal Article Pages 1-8 DOI 10.1007/s11661-012-1396-x Authors Medhat Awad El-Hadek, Department of Mechanical Design & Production, Faculty of Engineering at Port-Said, Port-Said University, Port-Fouad, Port-Said, 42523 Egypt Saleh Hamada Kaytbay, Department of Mechanical Engineering, Faculty of Engineering at Benha, Benha University, Benha, Egypt Journal Metallurgical and Materials Transactions A Online ISSN 1543-1940 Print ISSN 1073-5623

Description:    Community ecologists have attempted to explain species abundance distribution (SAD) shape for more than 80 years, but usually without relating SAD shape explicitly to ecological variables. We explored whether the scale (total assemblage abundance) and shape (assemblage evenness) of avifaunal SADs were related to ecological covariates. We used data on avifaunas, in-site habitat structure and landscape context that were assembled from previous studies; this amounted to 197 transects distributed across 16,000 km 2 of the box-ironbark forests of southeastern Australia. We used Bayesian conditional autoregressive models to link SAD scale and shape to these ecological covariates. Variation in SAD scale was relatable to some ecological covariates, especially to landscape vegetation cover and to tree height. We could not find any relationships between SAD shape and ecological covariates. SAD shape, the core component in SAD theory, may hold little information about how assemblages are governed ecologically and may result from statistical processes, which, if general, would indicate that SAD shape is not useful for distinguishing among theories of assemblage structure. Content Type Journal Article Category Community ecology - Original research Pages 1-9 DOI 10.1007/s00442-012-2438-1 Authors Jian D. L. Yen, Australian Centre for Biodiversity, School of Biological Sciences, Monash University, Clayton, VIC 3800, Australia James R. Thomson, Australian Centre for Biodiversity, School of Biological Sciences, Monash University, Clayton, VIC 3800, Australia Ralph Mac Nally, Australian Centre for Biodiversity, School of Biological Sciences, Monash University, Clayton, VIC 3800, Australia Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    The expression of prey antipredator defenses is often related to ambient consumer pressure, and prey express greater defenses under intense consumer pressure. Predation is generally greater at lower latitudes, and antipredator defenses often display a biogeographic pattern. Predation pressure may also vary significantly between habitats within latitudes, making biogeographic patterns difficult to distinguish. Furthermore, invasive predators may also influence the expression of prey defenses in ecological time. The purpose of this study was to determine how these factors influence the strength of antipredator responses. To assess patterns in prey antipredator defenses based upon geographic range (north vs. south), habitat type (wave-protected vs. wave-exposed shores), and invasive predators, we examined how native rock ( Cancer irroratus ) and invasive green ( Carcinus maenas ) crab predators influence the behavioral and morphological defenses of dogwhelk ( Nucella lapillus ) prey from habitats that differ in wave exposure across an ~230 km range within the Gulf of Maine. The expression of behavioral and morphological antipredatory responses varied according to wave exposure, geographic location, and predator species. Dogwhelks from areas with an established history with green crabs exhibited the largest behavioral and morphological antipredator responses to green crabs. Dogwhelk behavioral responses to rock crabs did not vary between habitats or geographic regions, although morphological responses were greater further south where predation pressure was greatest. These findings suggest that dogwhelk responses to invasive and native predators vary according to geographic location and habitat, and are strongly affected by ambient predation pressure due to the invasion history of an exotic predator. Content Type Journal Article Category Community ecology - Original research Pages 1-9 DOI 10.1007/s00442-012-2450-5 Authors Scott I. Large, Texas A&M University-Corpus Christi, Corpus Christi, TX 78412, USA Delbert L. Smee, Texas A&M University-Corpus Christi, Corpus Christi, TX 78412, USA Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Annual grass invasion into shrub-dominated ecosystems is associated with changes in nutrient cycling that may alter nitrogen (N) limitation and retention. Carbon (C) applications that reduce plant-available N have been suggested to give native perennial vegetation a competitive advantage over exotic annual grasses, but plant community and N retention responses to C addition remain poorly understood in these ecosystems. The main objectives of this study were to (1) evaluate the degree of N limitation of plant biomass in intact versus B. tectorum -invaded sagebrush communities, (2) determine if plant N limitation patterns are reflected in the strength of tracer 15 N retention over two growing seasons, and (3) assess if the strength of plant N limitation predicts the efficacy of carbon additions intended to reduce soil N availability and plant growth. Labile C additions reduced biomass of exotic annual species; however, growth of native A. tridentata shrubs also declined. Exotic annual and native perennial plant communities had divergent responses to added N, with B. tectorum displaying greater ability to use added N to rapidly increase aboveground biomass, and native perennials increasing their tissue N concentration but showing little growth response. Few differences in N pools between the annual and native communities were detected. In contrast to expectations, however, more 15 N was retained over two growing seasons in the invaded annual grass than in the native shrub community. Our data suggest that N cycling in converted exotic annual grasslands of the northern Intermountain West, USA, may retain N more strongly than previously thought. Content Type Journal Article Category Ecosystem ecology - Original research Pages 1-11 DOI 10.1007/s00442-012-2442-5 Authors Dana L. Witwicki, Environmental Sciences Graduate Program, Oregon State University, Corvallis, OR 97331, USA Paul S. Doescher, Department of Forest Ecosystems and Society, Oregon State University, 215 Peavy Hall, Corvallis, OR 97331, USA David A. Pyke, U.S. Geological Survey, Forest and Rangeland Ecosystem Science Center, 3200 SW Jefferson Way, Corvallis, OR 97331, USA Nicole M. DeCrappeo, U.S. Geological Survey, Forest and Rangeland Ecosystem Science Center, 3200 SW Jefferson Way, Corvallis, OR 97331, USA Steven S. Perakis, U.S. Geological Survey, Forest and Rangeland Ecosystem Science Center, 3200 SW Jefferson Way, Corvallis, OR 97331, USA Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Interactions between environmental stressors play an important role in shaping the health of an organism. This is particularly true in terms of the prevalence and severity of infectious disease, as stressors in combination will not always act to simply decrease the immune function of a host, but may instead interact to compound or even oppose the influence of parasitism on the health of an organism. Here, we explore the impact of environmental stress on host–parasite interactions using the water flea Daphnia magna and it is obligate parasite Pasteuria ramosa. Utilising an ecologically relevant stressor, we focus on the combined effect of salinity and P. ramosa on the fecundity and survival of the host, as well as on patterns of infectivity and the proliferation of the parasite. We show that in the absence of the parasite, host fecundity and survival was highest in the low salinity treatments. Once a parasite was introduced into the environment, however, salinity and parasitism acted antagonistically to influence both host survival and fecundity, and these patterns of disease were unrelated to infection rates or parasite spore loads. By summarising the form of interactions found in the broader Daphnia literature, we highlight how the combined effect of stress and parasitism will vary with the type of stressor, the trait used to describe the health of Daphnia and the host–parasite combination under observation. Our results highlight how the context-dependent nature of interactions between stress and parasitism inevitably complicates the link between environmental factors and the prevalence and severity of disease. Content Type Journal Article Category Physiological ecology - Original research Pages 1-8 DOI 10.1007/s00442-012-2452-3 Authors Matthew D. Hall, Zoologisches Institut, Evolutionsbiologie, University of Basel, Vesalgasse 1, 4051 Basel, Switzerland Andrea Vettiger, Zoologisches Institut, Evolutionsbiologie, University of Basel, Vesalgasse 1, 4051 Basel, Switzerland Dieter Ebert, Zoologisches Institut, Evolutionsbiologie, University of Basel, Vesalgasse 1, 4051 Basel, Switzerland Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Acidity is a major driving variable in the ecology of fresh waters, and we sought to quantify macroecological patterns in stream food webs across a wide pH gradient. We postulated that a few generalist herbivore-detritivores would dominate the invertebrate assemblage at low pH, with more specialists grazers at high pH. We also expected a switch towards algae in the diet of all primary consumers as the pH increased. For 20 stream food webs across the British Isles, spanning pH 5.0–8.4 (the acid sites being at least partially culturally acidified), we characterised basal resources and primary consumers, using both gut contents analysis and stable isotopes to study resource use by the latter. We found considerable species turnover across the pH gradient, with generalist herbivore-detritivores dominating the primary consumer assemblage at low pH and maintaining grazing. These were joined or replaced at higher pH by a suite of specialist grazers, while many taxa that persisted across the pH gradient broadened the range of algae consumed as acidity declined and increased their ingestion of biofilm, whose nutritional quality was higher than that of coarse detritus. There was thus an increased overall reliance on algae at higher pH, both by generalist herbivore-detritivores and due to the presence of specialist grazers, although detritus was important even in non-acidic streams. Both the ability of acid-tolerant, herbivore-detritivores to exploit both autochthonous and allochthonous food and the low nutritional value of basal resources might render chemically recovering systems resistant to invasion by the specialist grazers and help explain the sluggish ecological recovery of fresh waters whose water chemistry has ameliorated. Content Type Journal Article Category Community ecology - Original research Pages 1-13 DOI 10.1007/s00442-012-2421-x Authors Katrin Layer, School of Biological and Chemical Sciences, Queen Mary University of London, London, E1 4NS UK Alan G. Hildrew, School of Biological and Chemical Sciences, Queen Mary University of London, London, E1 4NS UK Guy Woodward, School of Biological and Chemical Sciences, Queen Mary University of London, London, E1 4NS UK Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    A series of Al-5 wt pct Si alloys with Yb additions (up to 6100 ppm) have been investigated using thermal analysis and multiscale microstructure characterization techniques. The addition of Yb was found to cause no modification effect to a fibrous morphology involving Si twinning; however, a refined plate-like eutectic structure was observed. The Al 2 Si 2 Yb phase was observed with Yb addition level of more than 1000 ppm. Within the eutectic Al and Si phases, the Al 2 Si 2 Yb phase was also found as a precipitation from the remained liquid. No Yb was detected in the α-Al matrix or plate-like Si particle, even with Yb addition up to 6100 ppm. The absence of Yb inside the eutectic Si particle may partly explain why no significant Si twinning was observed along {111} Si planes in the eutectic Si particle. In addition, the formation of the thermodynamic stable YbP phases is also proposed to deteriorate the potency of AlP phase in Al alloys. This investigation highlights to distinguish the modification associated with the ever present P in Al alloys. We define modification as a transition from faceted to fibrous morphology, while a reduction of the Si size is termed refinement. Content Type Journal Article Pages 1-13 DOI 10.1007/s11661-012-1410-3 Authors J. H. Li, Department of Metallurgy, University of Leoben, 8700 Leoben, Austria S. Suetsugu, Toyota Technological Institute, Hisakata 2-12-1, Tempaku, Nagoya, 468-8511 Japan Y. Tsunekawa, Toyota Technological Institute, Hisakata 2-12-1, Tempaku, Nagoya, 468-8511 Japan P. Schumacher, Department of Metallurgy, University of Leoben, 8700 Leoben, Austria Journal Metallurgical and Materials Transactions A Online ISSN 1543-1940 Print ISSN 1073-5623

Description:    Kitagawa-Takahashi diagram combines the endurance limit of a smooth specimen and the crack propagation threshold in a fracture mechanics specimen into single diagram thus providing the connection between the stress or strain-life and damage tolerance approaches. The diagram is modified by considering that (a) fatigue requires two independent load-parameters for unambiguous description, (b) long crack growth behavior defines the material resistance under constant stress amplitudes along with the associated R -ratio effects, (c) remote applied stresses and localized plasticity-effects can be combined to provide the total mechanical force opposing the material resistance leading to crack initiation, growth and failure describable in the diagram, (d) localized plasticity contributes to internal stresses that either augment or retard the remote stresses, and finally (e) the magnitude and gradient of these internal stresses determine the condition for propagation and/or non-propagation of the incipient cracks that form either at pre-existing stress concentrations or in situ formed stress concentrations due to localized plasticity. Localized plasticity forms the basis for the additional crack tip driving forces in either accelerating or decelerating crack growth kinetics thereby providing conditions for either crack arrest with resulting non-propagating cracks or for continuous uninterrupted crack growth. Internal stresses are generated during fatigue damage in the form of dislocation pile-ups, intrusions and extrusions. The analysis shows that critical magnitude and gradient of the internal stresses are required for an incipient crack to grow continuously, failing which crack arrest can occur. The methodology is based on separating the mechanically introduced crack tip driving forces vs the material resistance; the later can be extracted from long-crack growth data under constant amplitudes. Analysis of incipient short cracks growing under the elastic-plastic notch tip stress fields are analyzed systematically for various elastic stress concentrations, K t , and notch-tip radii, ρ. A general formulation is developed based on the calculations that can be incorporated into the unified life predication model that is being developed. Content Type Journal Article Category Symposium: Environmental Damage in Structural Materials Under Static/Dynamic Loads at Ambient Temperature Pages 1-15 DOI 10.1007/s11661-012-1416-x Authors K. Sadananda, Technical Data Analysis, 3190 Fairview Park Drive, Suite 650, Falls Church, VA 22042, USA S. Sarkar, Technical Data Analysis, 3190 Fairview Park Drive, Suite 650, Falls Church, VA 22042, USA Journal Metallurgical and Materials Transactions A Online ISSN 1543-1940 Print ISSN 1073-5623

Description:    Interference (cross-correlation) effects are present in the X-ray powder diffraction pattern of a polycrystalline aggregate. In an experimental diffraction pattern, the information is highly overlapped and can be confused with other effects. In this article, it is shown that the analysis of the patterns calculated from a cluster equilibrated via molecular dynamics simulation allows those effects to be separated. Extra intensity is observed, because of the presence of the grain boundaries contribution which is unexpectedly not that of an amorphous phase. Content Type Journal Article Category Symposium: Neutron and X-Ray Studies of Advanced Materials V Pages 1-6 DOI 10.1007/s11661-012-1428-6 Authors A. Leonardi, Department of Civil, Environmental and Mechanical Engineering, University of Trento, via Mesiano, 77, 38123 Trento, Italy M. Leoni, Department of Civil, Environmental and Mechanical Engineering, University of Trento, via Mesiano, 77, 38123 Trento, Italy P. Scardi, Department of Civil, Environmental and Mechanical Engineering, University of Trento, via Mesiano, 77, 38123 Trento, Italy Journal Metallurgical and Materials Transactions A Online ISSN 1543-1940 Print ISSN 1073-5623

Description:    Particle-stimulated nucleation (PSN) is investigated in Nb-containing ferritic stainless steel. Coarse-grained sheets were cold rolled to 80 pct thickness reduction and annealed from 973 K to 998 K (700 °C to 725 °C) to obtain partially recrystallized microstructures. Electron backscatter diffraction was performed around coarse niobium carbonitride particles (larger than 1  μ m) within coarse grains (~1 mm), with different host orientations in both deformed and annealed states. In the deformed state, the deformation zones around both spherical and rectangular particles were investigated. The local lattice rotations about the transverse direction necessary to accommodate the particle-matrix strain incompatibility were observed in all grains investigated. After annealing, recrystallization occurs preferentially around coarse particles at the initial stages of recrystallization. Based on a total number of 130 grains nucleated via PSN, we observe both, randomly oriented and minor {111}〈110〉 oriented texture components. The results also reveal that PSN in this material is not associated with a specific host orientation. Content Type Journal Article Pages 1-10 DOI 10.1007/s11661-012-1408-x Authors Rodrigo Pinto de Siqueira, Departamento de Engenharia de Materiais, Escola de Engenharia de Lorena, University of Sao Paulo, Lorena, SP 12600-970, Brazil Hugo Ricardo Zschommler Sandim, Departamento de Engenharia de Materiais, Escola de Engenharia de Lorena, University of Sao Paulo, Lorena, SP 12600-970, Brazil Dierk Raabe, Max-Planck Institut für Eisenforschung (MPIE), 40237 Düsseldorf, Germany Journal Metallurgical and Materials Transactions A Online ISSN 1543-1940 Print ISSN 1073-5623

Description:    This work analyzes the effect of different additions of silicon (0 to 5.0 pct) on the structure of a high-Chromium white cast iron, with chromium content of 16.8 pct and carbon 2.56 pct. The alloys were analyzed in both as-cast and heat-treated conditions. Casting was undertaken in metallic molds that yielded solidification rates faster than in commercial processes. Nevertheless, there was some degree of segregation of silicon; this segregation resulted in a refinement in the microstructure of the alloy. Silicon also generated a greater influence on the structure by destabilizing the austenitic matrix, and promoted greater precipitation of eutectic carbides. Above 3 pct silicon, pearlite formation occurred in preference to martensite. After the destabilization heat treatment, the matrix structure of the irons up to 3 pct Si consisted of secondary carbides in a martensitic matrix with some retained austenite; higher Si additions produced a ferritic matrix. The different as-cast and heat-treated microstructures were correlated with selected mechanical properties such as hardness, matrix microhardness, and fracture toughness. Silicon additions increased matrix microhardness in the as-cast conditions, but the opposite phenomenon occurred in the heat-treated conditions. Microhardness decreased as silicon content was increased. Bulk hardness showed the same behavior. Fracture toughness was observed to increase up to 2 pct Si, and then decreased for higher silicon contents. These results are discussed in terms of the effect of eutectic carbides’ size and the resulting matrix due to the silicon additions. Content Type Journal Article Pages 1-17 DOI 10.1007/s11661-012-1434-8 Authors A. Bedolla-Jacuinde, Instituto de Investigaciones Metalúrgicas, Universidad Michoacana de San Nicolás de Hidalgo, Mexico, Mexico M. W. Rainforth, Department of Engineering Materials, The University of Sheffield, Sheffield, U.K. I. Mejía, Instituto de Investigaciones Metalúrgicas, Universidad Michoacana de San Nicolás de Hidalgo, Mexico, Mexico Journal Metallurgical and Materials Transactions A Online ISSN 1543-1940 Print ISSN 1073-5623

Description: HSLA-100 steel with high content of alloying elements (nominally in wt pct, 3.5 Ni, 1.6 Cu, and 0.6Mo) is now used to produce heavy plates for constructing a hull and drilling platform. We proposed here a substantially leaner steel composition (containing 1.7 Ni, 1.1 Cu, and 0.5Mo) to produce a heavy plate to 80 mm thickness with mechanical properties comparable with those of the HSLA-100 grade. A continuous cooling transformation (CCT) diagram of the steel was constructed. Key parameters of thermal treatment and revealing mechanisms of strengthening and toughening were derived based on industrial production trials. The microstructures of the 80-mm-thick plate were lath-like bainite (LB) at near surface of the quarter thickness ( t /4), and granular bainite (GB)+LB at center thickness ( t /2) after solutionizing and water quenching (Q). The effect of tempering (T) on the microstructures and properties of the plate was investigated. Excellent combination of room temperature strength and low-temperature Charpy V-notch (CVN) toughness approximately equivalent to that of the HSLA 100 grade (YS 〉 690 MPa, CVN energy 〉100 J even at 193 K [−80 °C]) was achieved in the plate treated by the QT process with tempering temperature of 898 K (625 °C). The combination of strength and toughness at t /4 is superior to that at t /2 of the plate under both as-quenched and QT conditions. This result is attributed to that the fraction of high-angle grain boundaries (HAGBs) at t /4 is higher than that at t /2. Content Type Journal Article Pages 1-16 DOI 10.1007/s11661-012-1389-9 Authors Dongsheng Liu, Institute of Research of Iron and Steel, Shasteel, Jinfeng, Zhangjiagang, 215625 Jiangsu, People’s Republic of China Binggui Cheng, Institute of Research of Iron and Steel, Shasteel, Jinfeng, Zhangjiagang, 215625 Jiangsu, People’s Republic of China Yuanyuan Chen, Institute of Research of Iron and Steel, Shasteel, Jinfeng, Zhangjiagang, 215625 Jiangsu, People’s Republic of China Journal Metallurgical and Materials Transactions A Online ISSN 1543-1940 Print ISSN 1073-5623

Description: The atomic and electronic structures of several Ca-Mg-TM amorphous alloys (TM is Cu or Zn) have been analyzed using ab initio molecular dynamics simulation and neutron diffraction. Partial pair distribution functions have been produced and the pair bond distances and partial coordination numbers have been reported for these alloys. Similarities and differences in the amorphous structures of the Ca-Mg-Cu and Ca-Mg-Zn alloys have been discussed. Strong interactions between Ca-Cu, Mg-Cu and Ca-Zn atom pairs rooted from the orbital hybridization of the s - p - d electrons have been recognized to result in noticeable shortening of respective atom pair bond distances and pronounced chemical short range ordering near the TM atoms. Voronoi tessellation analysis has shown that the polytetrahedral-type clusters and five-coordinated atom pairs dominate in the amorphous structures, which indicates that tetrahedra and pentagonal bi-pyramids are the main building blocks in these amorphous alloys. Content Type Journal Article Category Symposium: Bulk Metallic Glasses IX Pages 1-10 DOI 10.1007/s11661-012-1406-z Authors O. N. Senkov, UES, Inc., Dayton, OH, USA Y. Q. Cheng, Chemical and Engineering Materials Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA Journal Metallurgical and Materials Transactions A Online ISSN 1543-1940 Print ISSN 1073-5623

Description:    The current investigation reports detailed study on the microstructural evolution in the suction cast hypereutectic Ti 71 Fe 29− x Sn x alloys during Sn addition with x  = 0, 2, 2.5, 3, 3.85, 4.5, 6, and 10 at. pct and the solidification of these ternary alloys using SEM and TEM. These alloys have been prepared by melting high-purity elements using vacuum arc melting furnace under high-purity argon atmosphere. This was followed by suction casting these alloys in the water-cooled split Cu molds of diameters, ϕ = 1 and 3 mm, under argon atmosphere. The results indicate the formation of binary eutectic between bcc solid solution β-Ti and B2 FeTi in all alloys. β-Ti undergoes eutectoid transformation, β-Ti → α-Ti + FeTi, during subsequent solid-state cooling, leading to formation of hcp α-Ti and FeTi. For alloys x  〈 2, the primary FeTi forms from the liquid before the formation of eutectic with minute scale Ti 3 Sn phase. For alloys with 2 ≥  x  ≤ 10, the liquid is found to undergo ternary quasi-peritectic reaction with primary Ti 3 Sn, L+Ti 3 Sn → β-Ti+FeTi, leading to formation of another kind of FeTi. In all the other alloy compositions (3.85 ≥  x  ≤ 10), Ti 3 Sn and FeTi dendrites are observed in the suction cast alloys with profuse amount of Ti 3 Sn being formed for alloys with x  ≥ 4.5. The current study conclusively proves that the liquid undergoes ternary quasi-peritectic reaction involving four phases, L + Ti 3 Sn → β-Ti + FeTi, which lies at the invariant point Ti 69.2±0.8 Fe 27.4±0.7 Sn 3.4±0.2 (denoted by P). Below P, there is one univariant reaction, i.e. , L → β-Ti + FeTi for all alloy compositions, whereas above P, liquid undergoes one of the univariant reactions, i.e. , L + β-Ti → Ti 3 Sn (Sn = 2, 2.5, 3, and 4.5 at. pct) or L + FeTi → Ti 3 Sn for alloys (Sn = 6, 10 at. pct). For alloy with Sn = 3.85 at. pct, the ternary quasi-peritectic reaction is co-operated by two monovariant eutectic reactions, i.e. , L → β-Ti + FeTi below P and L → FeTi + Ti 3 Sn above P. Detailed microstructural information allows us to construct liquidus projection of the investigated alloys. The results are critically discussed in the light of available literature data. Content Type Journal Article Pages 1-13 DOI 10.1007/s11661-012-1404-1 Authors Sumanta Samal, Department of Materials Science and Engineering, Indian Institute of Technology Kanpur, Kanpur, 208016 Uttar Pradesh, India Barnali Mondal, Department of Materials Science and Engineering, Indian Institute of Technology Kanpur, Kanpur, 208016 Uttar Pradesh, India Krishanu Biswas, Department of Materials Science and Engineering, Indian Institute of Technology Kanpur, Kanpur, 208016 Uttar Pradesh, India Govind, Materials Science Division, Vikram Sarabhai Space Centre, Indian Space Research Organisation, Trivandrum, 695022 Kerala, India Journal Metallurgical and Materials Transactions A Online ISSN 1543-1940 Print ISSN 1073-5623

Description:    Material strengthening and embrittlement are controlled by complex intrinsic interactions between dislocations and hydrogen-induced defect structures that strongly alter the observed deformation mechanisms in materials. In this study, we reported molecular statics simulations at zero temperature for pure α-Fe with a single H atom at an interstitial and vacancy site, and two H atoms at an interstitial and vacancy site for each of the 〈100〉, 〈110〉, and 〈111〉 symmetric tilt grain boundary (STGB) systems. Simulation results show that the grain boundary (GB) system has a smaller effect than the type of H defect configuration (interstitial H, H-vacancy, interstitial 2H, and 2H-vacancy). For example, the segregation energy of hydrogen configurations as a function of distance is comparable between symmetric tilt GB systems. However, the segregation energy of the 〈100〉 STGB system with H at an interstitial site is 23 pct of the segregation energy of 2H at a similar interstitial site. This implies that there is a large binding energy associated with two interstitial H atoms in the GB. Thus, the energy gained by this H-H reaction is ~54 pct of the segregation energy of 2H in an interstitial site, creating a large driving force for H atoms to bind to each other within the GB. Moreover, the cohesive energy values of 125 STGBs were calculated for various local H concentrations. We found that as the GB energy approaches zero, the energy gained by trapping more hydrogen atoms is negligible and the GB can fail via cleavage. These results also show that there is a strong correlation between the GB character and the trapping limit (saturation limit) for hydrogen. Finally, we developed an atomistic modeling framework to address the probabilistic nature of H segregation and the consequent embrittlement of the GB. These insights are useful for improving ductility by reengineering the GB character of polycrystalline materials to alter the segregation and embrittlement behavior in α-Fe. Content Type Journal Article Category Symposium: Environmental Damage in Structural Materials under Static/Dynamic Loads at Ambient Temperature Pages 1-11 DOI 10.1007/s11661-012-1430-z Authors Kiran N. Solanki, School for Engineering of Matter, Transport, and Energy, Arizona State University, Tempe, AZ 85287, USA Mark A. Tschopp, Center for Advanced Vehicular Systems, 200 Research Blvd., Starkville, MS 39759, USA Mehul A. Bhatia, School for Engineering of Matter, Transport, and Energy, Arizona State University, Tempe, AZ 85287, USA Nathan R. Rhodes, Center for Advanced Vehicular Systems, 200 Research Blvd., Starkville, MS 39759, USA Journal Metallurgical and Materials Transactions A Online ISSN 1543-1940 Print ISSN 1073-5623

Description:    Shear localizations with different strains in annealed copper were obtained by a modified split Hopkinson pressure bar. Microstructure and microtexture evolution of the shear localization regions were examined using optical microscopy, electron backscatter diffraction technique, and transmission electron microscopy. The results show that both the mechanical response and deformation behavior are correlated closely to the shear strains. The elongated dislocation cells, stretched subgrains, and the refinement of subgrains are observed within shear localizations during dynamic deformation. Ultrafine grains of 100 to 300 nm with high-angle-boundaries are produced within the shear band with the shear strain of 5.8. Microtexture characterization reveals that a stable orientation, in which 〈110〉 directions of the crystals tend to align with the shear direction, develops both in the deformation and recrystallization areas. The {111} planes of the crystals tend to parallel to the shear plane in the deformation area, whereas the aggregated extent of this orientation becomes weak in the recrystallization area. In addition, some grains exist with the {100} planes parallel to the shear plane in the deformation and recrystallization areas. The rotational dynamic recrystallization is a reasonable mechanism for the microstructure evolution. The effects of cooling stage on the growth of grains and the change of dislocation density are estimated as a complementarity to this mechanism. Content Type Journal Article Pages 1-13 DOI 10.1007/s11661-012-1421-0 Authors Lin Tang, School of Materials Science and Engineering, Central South University, Changsha, 410083 P.R. China Zhiyong Chen, School of Materials Science and Engineering, Central South University, Changsha, 410083 P.R. China Congkun Zhan, School of Materials Science and Engineering, Central South University, Changsha, 410083 P.R. China Xuyue Yang, School of Materials Science and Engineering, Central South University, Changsha, 410083 P.R. China Chuming Liu, School of Materials Science and Engineering, Central South University, Changsha, 410083 P.R. China Journal Metallurgical and Materials Transactions A Online ISSN 1543-1940 Print ISSN 1073-5623

Description:    Silver-tin oxide electrical contact material with 10 wt pct stannic oxide and balance nanosized and micronsized silver was developed successfully. Stannic oxide particles chemically coated by a layer of silver nanospheres are homogeneously dispersed in a silver microcrystalline matrix made by chemical synthesis. The material processed by pressing-sintering-repressing exhibited enhanced properties: density: 97.1 to 97.9 pct relative density, Vickers hardness: 103 to 115, electrical conductivity: 65 to 69 pct IACS, volumetric shrinkage: 28.9 to 30.9 pct, and a very fine and uniform microstructure. Content Type Journal Article Category Communication Pages 1-6 DOI 10.1007/s11661-012-1424-x Authors Magdalena Lungu, National Institute for Research and Development in Electrical Engineering ICPE-CA, 030138 Bucharest 3, Romania Stefania Gavriliu, National Institute for Research and Development in Electrical Engineering ICPE-CA, 030138 Bucharest 3, Romania Elena Enescu, National Institute for Research and Development in Electrical Engineering ICPE-CA, 030138 Bucharest 3, Romania Mariana Lucaci, National Institute for Research and Development in Electrical Engineering ICPE-CA, 030138 Bucharest 3, Romania Violeta Tsakiris, National Institute for Research and Development in Electrical Engineering ICPE-CA, 030138 Bucharest 3, Romania Gimi Rimbu, National Institute for Research and Development in Electrical Engineering ICPE-CA, 030138 Bucharest 3, Romania Journal Metallurgical and Materials Transactions A Online ISSN 1543-1940 Print ISSN 1073-5623

Description:    Al 413/Mg couples were prepared by the compound casting process. Characterization of the interface by an optical microscope and scanning electron microscope (SEM) showed that a relatively uniform interface composed of three different layers is formed at the interface. The thickness of the interface depended on the melt/insert volume ratio (VR) significantly and was 80 and 470  μm  in 1.25 and 3 VRs, respectively. The results of the energy dispersive X-ray spectroscopy (EDS), wavelength dispersive X-ray spectroscopy (WDS), and X-ray diffraction analysis showed that the interface layers are mainly composed of Al 3 Mg 2 , Al 12 Mg 17 , and Mg 2 Si intermetallic compounds. An accumulation of magnesium oxide films was detected within the (Al 12 Mg 17  +  δ ) eutectic structure of the interface next to the magnesium base metal. Despite different thicknesses of the interface, shear strengths of the Al 413/Mg couples prepared in 1.25 and 3 VRs were almost same. The study of the fracture surfaces of the Al 413/Mg couples revealed that the accumulated magnesium oxide films act as a weak point for initiation of longitudinal cracks and failure of the joint. Content Type Journal Article Pages 1-11 DOI 10.1007/s11661-012-1296-0 Authors E. Hajjari, Department of Metallurgy and Materials Engineering, Iran University of Science and Technology, 16846-13114 Tehran, Iran M. Divandari, Department of Metallurgy and Materials Engineering, Iran University of Science and Technology, 16846-13114 Tehran, Iran S. H. Razavi, Department of Metallurgy and Materials Engineering, Iran University of Science and Technology, 16846-13114 Tehran, Iran T. Homma, Research Center for Advanced Magnesium Technology, Nagaoka University of Technology, Nagaoka, 940-2188 Japan S. Kamado, Research Center for Advanced Magnesium Technology, Nagaoka University of Technology, Nagaoka, 940-2188 Japan Journal Metallurgical and Materials Transactions A Online ISSN 1543-1940 Print ISSN 1073-5623

Description:    A stable Ni-rich Ni-29.7Ti-20Hf (at. pct) shape memory alloy, with relatively high transformation temperatures, was shown to exhibit promising properties at lower raw material cost when compared to typical NiTi-X (X = Pt, Pd, Au) high-temperature shape memory alloys (HTSMAs). The excellent dimensional stability and high work output for this alloy were attributed to a coherent, nanometer size precipitate phase observed using transmission electron microscopy. To establish an understanding of the role of these precipitates on the microstructure and ensuing stability of the NiTiHf alloy, a detailed study of the micromechanical and microstructural behaviors was performed. In-situ neutron diffraction at stress and temperature was used to obtain quantitative information on phase-specific internal strain, texture, and phase volume fractions during both isothermal and isobaric testing of the alloy. During isothermal testing, the alloy exhibited low isothermal strains due to limited detwinning, consistent with direct measurements of the bulk texture through neutron diffraction. This limited detwinning was attributed to the pinning of twin and variant boundaries by the dispersion of fine precipitates. During isobaric thermal cycling at 400 MPa, the high work output and near-perfect dimensional stability was attributed to the presence of the precipitates that act as homogeneous sources for the nucleation of martensite throughout the material, while providing resistance to irrecoverable processes such as plastic deformation. Content Type Journal Article Pages 1-14 DOI 10.1007/s11661-012-1297-z Authors O. Benafan, Advanced Materials Processing and Analysis Center (AMPAC), Mechanical, Materials, and Aerospace Engineering, University of Central Florida, Orlando, FL 32816, USA R. D. Noebe, Structures and Materials Division, NASA Glenn Research Center, Cleveland, OH 44135, USA S. A. Padula II, Structures and Materials Division, NASA Glenn Research Center, Cleveland, OH 44135, USA R. Vaidyanathan, Advanced Materials Processing and Analysis Center (AMPAC), Mechanical, Materials, and Aerospace Engineering, University of Central Florida, Orlando, FL 32816, USA Journal Metallurgical and Materials Transactions A Online ISSN 1543-1940 Print ISSN 1073-5623

Description:    Steel is a particularly challenging material to semisolid process because of the high temperatures involved and the potential for surface oxidation. Hot-rolled X210CrW12 tool steel was applied as a feedstock for thixoforming. The samples were heated up to 1525 K (1250 °C) to obtain 30 pct of the liquid phase. They were pressed in the semisolid state into a die preheated up to 473 K (200 °C) using a device based on a high-pressure die casting machine. As a result, a series of main bucket tooth thixo-casts for a mining combine was obtained. The microstructure of the thixo-cast consisted of austenite globular grains (average grain size 46 μ m) surrounded by a eutectic mixture (ferrite, austenite, and M 7 C 3 carbides). The average hardness of primary austenite grains was 470 HV 0.02 and that of eutectic 551 HV 0.02 . The X-ray analysis confirmed the presence of 11.8 pct α -Fe, 82.4 pct γ -Fe, and 5.8 pct M 7 C 3 carbides in the thixo-cast samples. Thermal and dilatometric effects were registered in the solid state, and the analysis of curves enabled the determination of characteristic temperatures of heat treatment: 503 K, 598 K, 693 K, 798 K, 828 K, 903 K, and 953 K (230 °C, 325 °C, 420 °C, 525 °C, 555 °C, 630 °C, 680 °C). The thixo-casts were annealed at these temperatures for 2 hours. During annealing in the temperature range 503 K to 693 K (230 °C to 420 °C), the hardness of primary globular grains continuously decreased down to 385HV 0.02 . The X-ray diffraction showed a slight shift of peaks responsible for the tension release. Moreover, after the treatment at 693 K (420 °C), an additional peak from precipitated carbides was observed in the X-ray diffraction. Thin plates of perlite (average hardness 820 HV 0.02 ) with carbide precipitates appeared at the boundaries of globular grains at 798 K (525 °C). They occupied 17 pct of the grain area. Plates of martensite were found in the center of grains, while the retained austenite was observed among them (average hardness of center grains was 512 HV 0.02 ). A nearly complete decomposition of metastable austenite was achieved after tempering at 828 K (555 °C) due to prevailing lamellar pearlite structure starting at grain boundaries and the martensite located in the center of the grains. The X-ray analysis confirmed the presence of 3.4 pct γ -Fe, 84.6 pct α -Fe, and 12 pct M 7 C 3 carbides. The dilatometric analysis showed that the transformation of metastable austenite into martensite took place during cooling from 828 K (555 °C). The additional annealing at 523 K (250 °C) for 2 hours after heat treatment at 828 K (555 °C) caused the precipitation of carbides from the martensite. After tempering at 903 K (630 °C), the thixo-cast microstructure showed globular grains consisting mainly of thick lamellar perlite of the average hardness 555 HV 0.02 . Content Type Journal Article Pages 1-10 DOI 10.1007/s11661-012-1347-6 Authors Łukasz Rogal, Institute of Metallurgy and Materials Science of the Polish Academy of Sciences, Krakow, 30-059 Poland Jan Dutkiewicz, Institute of Metallurgy and Materials Science of the Polish Academy of Sciences, Krakow, 30-059 Poland Journal Metallurgical and Materials Transactions A Online ISSN 1543-1940 Print ISSN 1073-5623

Description:    This study investigated the influence of the duration of milling on the formation of TiC-reinforced iron composite through carbothermal reduction of a hematite and anatase mixture. Mixtures of hematite, anatase, and graphite powders were mechanically activated in a planetary ball mill in an argon atmosphere with different milling times (0 to 60 hours). X-ray diffraction showed that with increasing milling time, the crystallite size of the hematite decreased to nanometer range, accompanied by an increment in internal strain. Prolonging the milling process increased dislocation density of the as-milled powder. The as-milled powder was consolidated by cold pressing under 100 MPa and sintered in vacuum at 1373 K (1100 °C). High temperature during sintering resulted in the formation of iron and titanium carbide phases as confirmed by X-ray diffraction, scanning electron microscope, and energy dispersive X-ray analysis. Without mechanically activated milling, the reaction forming TiC did not occur during sintering at 1373 K (1100 °C), indicating a reduction in reaction temperature promoted by mechanical milling. An increase in milling time resulted in an increase in sintered density and hardness due to the fineness of the composite powder, together with complete TiC and iron phase formation. Content Type Journal Article Pages 1-11 DOI 10.1007/s11661-012-1440-x Authors Hussain Zuhailawati, School of Materials and Mineral Resources Engineering, Universiti Sains Malaysia, Engineering Campus, 14300 Nibong Tebal, Penang, Malaysia Mohd Salihin Hassin, School of Materials and Mineral Resources Engineering, Universiti Sains Malaysia, Engineering Campus, 14300 Nibong Tebal, Penang, Malaysia Samayamutthirian Palaniandy, JKMRC University of Queensland, 40 Isles Road, Indooroopilly, QLD 4068, Australia Journal Metallurgical and Materials Transactions A Online ISSN 1543-1940 Print ISSN 1073-5623

Description:    Admixing pure elements to powder mixes can cause the formation of heterogeneous microstructures in sintered parts. For instance, nickel is renowned for forming nickel-rich areas (NRA) in powder metallurgy (PM) nickel steels due to its poor diffusivity in iron matrix (or lattice). The present work is aimed at characterizing the principal diffusion mechanisms of nickel and their influence on microstructures and properties of PM nickel steels. A new wavelength dispersive X-ray spectrometry (WDS) approach linking line scans and X-ray maps to concentration maps is proposed. Grain boundary and volume diffusion coefficients of admixed nickel have been determined in PM nickel steels using Suzuoka’s equation. Results also show that nickel distributes itself in the iron matrix mainly by surface and grain boundary diffusion. Content Type Journal Article Pages 1-12 DOI 10.1007/s11661-012-1417-9 Authors Bernard Tougas, Department of Mining, Metallurgical and Materials Engineering, Université Laval, 1065 De la Médecine, Quebec, QC G1V 0A6, Canada Carl Blais, Department of Mining, Metallurgical and Materials Engineering, Université Laval, 1065 De la Médecine, Quebec, QC G1V 0A6, Canada François Chagnon, Rio Tinto Metal Powders, 1655 rte Marie-Victorin, Sorel-Tracy, QC J3R 4R4, Canada Sylvain Pelletier, National Research Council of Canada, 75 boul. de Mortagne, Boucherville, QC J4B 6Y4, Canada Journal Metallurgical and Materials Transactions A Online ISSN 1543-1940 Print ISSN 1073-5623

Description:    There is a growing demand for single-use disposable polymer devices with features at submicron scales. This requires resilient tooling which can be patterned to scales of the order of hundreds of nanometers. The requisite topology can be imparted to silicon, but it is too brittle to be of use in a die to mold thousands of plastic parts. The polycrystalline nature of tool steel means that it cannot be patterned with submicron detail. Some bulk amorphous alloys have the requisite mechanical properties to be viable as materials for such dies, and can be patterned— e.g. , via embossing as a supercooled liquid into MEMS silicon or using focused ion beam (FIB)—with submicron features which may persevere over many thousands of molding cycles. The composition of the amorphous alloy must be carefully selected to suit the particular molding application (polymer/process). The state-of-the-art methodology is presented, along with results of our recent experimental investigations. Content Type Journal Article Category Symposium: Bulk Metallic Glasses IX Pages 1-10 DOI 10.1007/s11661-012-1427-7 Authors David J. Browne, School of Mechanical & Materials Engineering, University College Dublin, Belfield, Dublin 4, Ireland Dermot Stratton, School of Mechanical & Materials Engineering, University College Dublin, Belfield, Dublin 4, Ireland Michael D. Gilchrist, School of Mechanical & Materials Engineering, University College Dublin, Belfield, Dublin 4, Ireland Cormac J. Byrne, School of Mechanical & Materials Engineering, University College Dublin, Belfield, Dublin 4, Ireland Journal Metallurgical and Materials Transactions A Online ISSN 1543-1940 Print ISSN 1073-5623

Description:    Chronic atmospheric N deposition has modified relative N availability, altering the biogeochemical cycles of forests and the stoichiometry of nutrients in trees, inducing P limitation, and modifying the N:P ratios of plant biomass. This study examines how the variation in the foliar stoichiometry of Abies pinsapo across an N deposition gradient affects foliar traits and photosynthetic rate. We measured the maximum net assimilation rates ( A max ) and the foliar nitrogen (N) and phosphorus (P) concentrations in A. pinsapo needles of five age classes. The leaf mass per area and photosynthetic N and P use efficiencies (PNUE and PPUE, respectively) were also estimated. The results from the N-saturated stand (Sierra Bermeja, B) differed from the comparable N-limited stands under investigation (Yunquera, Y, and Sierra Real, SR). The trees from Y and SR exhibited a reduction in the N content in older needles, whereas the foliar N concentration at the B site increased with needle age. N and P were positively correlated at Y and SR, but not at B, suggesting that the overload of N in the trees at site B has exceeded the homeostatic regulation capacity of the N-saturated stand in terms of foliar stoichiometry. A max and PNUE were correlated positively with P and negatively with the N/P ratio at the three study sites. The foliar N concentration was positively correlated with A max at Y and SR. However, this relationship was negative for the B site. These findings suggest that the nutritional imbalance caused by increased chronic deposition of N and an insufficient supply of P counteracts the potential increase in net photosynthesis induced by the accumulation of foliar N. Content Type Journal Article Category Physiological ecology - Original research Pages 1-12 DOI 10.1007/s00442-012-2454-1 Authors Mª Carmen Blanes, Departamento de Biología Animal, Biología Vegetal y Ecología (Ecología), Facultad de Ciencias Experimentales, Universidad de Jaén, 23009 Jaén, Spain Benjamín Viñegla, Departamento de Biología Animal, Biología Vegetal y Ecología (Ecología), Facultad de Ciencias Experimentales, Universidad de Jaén, 23009 Jaén, Spain José Merino, Departamento de Sistemas Físicos, Químicos y Naturales, Facultad de Ciencias Experimentales, Universidad Pablo de Olavide, 41013 Sevilla, Spain José A. Carreira, Departamento de Biología Animal, Biología Vegetal y Ecología (Ecología), Facultad de Ciencias Experimentales, Universidad de Jaén, 23009 Jaén, Spain Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    For species with complex life cycles, transitions between life stages result in niche shifts that are often associated with evolutionary trade-offs. When conditions across life stages are unpredictable, plasticity in niche shift timing may be adaptive; however, factors associated with clutch identity (e.g., genetic or maternal) may influence the effects of such plasticity. The red-eyed treefrog ( Agalychnis callidryas ) is an ideal organism for investigating the effects of genetics and life stage switch point timing because embryos exhibit adaptive phenotypic plasticity in hatching time. In this study, we evaluated the effects of experimentally manipulated hatching time and clutch identity on antipredator behavior of tadpoles and on developmental traits of metamorphs, including larval period, mass, SVL, and jumping ability. We found that in the presence of dragonfly nymph predator cues at 21 days post-oviposition, tadpoles reduced both their activity level and height in the water column. Furthermore, early-hatched tadpoles were less active than late-hatched tadpoles of the same age. This difference in behavior patterns of early- and late-hatched tadpoles may represent an adaptive response due to a longer period of susceptibility to odonate predators for early-hatched tadpoles, or it may be a carry-over effect mediated by early exposure to an environmental stressor (i.e., induction of early hatching). We also found that hatching time affected both behavioral traits and developmental traits, but its effect on developmental traits varied significantly among clutches. This study shows that a single early-life event may influence a suite of factors during subsequent life stages and that some of these effects appear to be dependent on clutch identity. This interaction may represent an evolutionary response to a complex life cycle and unpredictable environments, regardless of whether the clutch differences are due to additive genetic variance or maternal effects. Content Type Journal Article Category Behavioral ecology - Original research Pages 1-13 DOI 10.1007/s00442-012-2443-4 Authors Megan E. Gibbons, Department of Biology, Birmingham-Southern College, Birmingham, AL 35254, USA M. Patricia George, Department of Biology, Birmingham-Southern College, Birmingham, AL 35254, USA Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    One of the essential requirements for an introduced plant species to become invasive is an ability to reproduce outside the native range, particularly when initial populations are small. If a reproductive Allee effect is operating, plants in small populations will have reduced reproductive success relative to plants in larger populations. Alternatively, if plants in small populations experience less competition for pollination than those in large populations, they may actually have higher levels of reproductive success than plants in large populations. To resolve this uncertainty, we investigated how the per capita fecundity of plants was affected by population size in three invasive milkweed species. Field surveys of seed production in natural populations of different sizes but similar densities were conducted for three pollinator-dependent invasive species, namely Asclepias curassavica, Gomphocarpus fruticosus and G. physocarpus . Additionally, supplemental hand-pollinations were performed in small and large populations in order to determine whether reproductive output was limited by pollinator activity in these populations. Reproductive Allee effects were not detected in any of the study species. Instead, plants in small populations exhibited remarkably high levels of reproductive output compared to those in large populations. Increased fruit production following supplemental hand-pollinations suggested that the lower reproductive output of naturally pollinated plants in large populations is a consequence of pollen limitation rather than limitation due to abiotic resources. This is consistent with increased intraspecific competition for pollination amongst plants in large populations. It is likely that the invasion of these milkweed species in Australia has been enhanced because plants in small founding populations experience less intraspecific competition for pollinators than those in large populations, and thus have the ability to produce copious amounts of seeds. Content Type Journal Article Category Population ecology - Original research Pages 1-9 DOI 10.1007/s00442-012-2463-0 Authors Megan Ward, School of Biological Sciences, The University of Queensland, Brisbane, QLD 4072, Australia Steven D. Johnson, DST-NRF Centre for Invasion Biology, School of Biological and Conservation Sciences, University of KwaZulu-Natal, P. Bag X01, Scottsville, Pietermaritzburg, 3209 South Africa Myron P. Zalucki, School of Biological Sciences, The University of Queensland, Brisbane, QLD 4072, Australia Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Introduced species can alter the topology of food webs. For instance, an introduction can aid the arrival of free-living consumers using the new species as a resource, while new parasites may also arrive with the introduced species. Food-web responses to species additions can thus be far more complex than anticipated. In a subarctic pelagic food web with free-living and parasitic species, two fish species (arctic charr Salvelinus alpinus and three-spined stickleback Gasterosteus aculeatus ) have known histories as deliberate introductions. The effects of these introductions on the food web were explored by comparing the current pelagic web with a heuristic reconstruction of the pre-introduction web. Extinctions caused by these introductions could not be evaluated by this approach. The introduced fish species have become important hubs in the trophic network, interacting with numerous parasites, predators and prey. In particular, five parasite species and four predatory bird species depend on the two introduced species as obligate trophic resources in the pelagic web and could therefore not have been present in the pre-introduction network. The presence of the two introduced fish species and the arrival of their associated parasites and predators increased biodiversity, mean trophic level, linkage density, and nestedness; altering both the network structure and functioning of the pelagic web. Parasites, in particular trophically transmitted species, had a prominent role in the network alterations that followed the introductions. Content Type Journal Article Category Community ecology - Original research Pages 1-10 DOI 10.1007/s00442-012-2461-2 Authors Per-Arne Amundsen, Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, University of Tromsø, 9037 Tromso, Norway Kevin D. Lafferty, U.S. Geological Survey, Western Ecological Research Center, c/o Marine Science Institute, UC Santa Barbara, Santa Barbara, CA 93106, USA Rune Knudsen, Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, University of Tromsø, 9037 Tromso, Norway Raul Primicerio, Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, University of Tromsø, 9037 Tromso, Norway Roar Kristoffersen, Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, University of Tromsø, 9037 Tromso, Norway Anders Klemetsen, Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, University of Tromsø, 9037 Tromso, Norway Armand M. Kuris, Department of Ecology, Evolution and Marine Biology, and Marine Science Institute, University of California, Santa Barbara, CA 93106, USA Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    A centrifugally cast 20Cr32Ni1Nb stainless steel manifold in service for 16 years at temperatures ranging from 1073 K to 1123 K (800 °C to 850 °C) has been characterized using scanning electron microscopy (SEM), electron probe micro-analysis (EPMA), auger electron spectroscopy (AES), and X-ray diffraction (XRD). Nb(C,N), M 23 C 6 , and the silicide G-phases (Ni 16 Nb 6 Si 7 ) were all identified in a conventional SEM, while the nitride Z-phase (CrNbN) was observed only in AES. M 23 C 6 , Z-phase and G-phase were characterized in XRD. Thermodynamic equilibrium calculations using ThermoCalc Version S, with the TCS Steel and Fe-alloys Database (TCFE6), and Thermotech Ni-based Superalloys Database (TTNI8) were validated by comparing experimental phase fraction results obtained from both EPMA and AES. A computational study looking at variations in the chemical composition of the alloy, and how they affect phase equilibria, was investigated. Increasing the nitrogen concentration is shown to decrease G-phase formation, where it is replaced by other intermetallic phases such as Z-phase and π -phase that do not experience liquation during pre-weld annealing treatments. Suppressing G-phase formation was ultimately determined to be a function of minimizing silicon content, and understabilizing the Nb/(C + 6/7N) ratio. Content Type Journal Article Pages 1-13 DOI 10.1007/s11661-012-1457-1 Authors Matthew P. Dewar, Department of Chemical and Materials Engineering, University of Alberta, Edmonton, AB T6G 2V4, Canada Adrian P. Gerlich, University of Waterloo, Waterloo, ON, Canada Journal Metallurgical and Materials Transactions A Online ISSN 1543-1940 Print ISSN 1073-5623

Description:    W-5.6Ni-1.4Fe heavy alloys were prepared by the method of spark-plasma sintering, and the densification and grain growth kinetics were analyzed as a function of various parameters such as sintering temperature and dwell duration. It is found that the local temperature gradient at the vicinity of the pores can cause the matrix phase melting or softening, resulting in a viscous layer coating the W particles and an improved solubility of W into the matrix phase. In the initial stage, particle rearrangement and neck formation and growth take place, and γ -(Ni, Fe) matrix phase has formed. Dissolution-precipitation and Ni-enhanced W grain boundary diffusion together with viscous process contribute to the simultaneous densification and grain growth in the intermediate stage. During the final stage, fast grain growth, controlled by both gas-phase diffusion and dissolution-precipitation mechanisms, dominates over the densification. Content Type Journal Article Pages 1-11 DOI 10.1007/s11661-012-1454-4 Authors Ke Hu, National Engineering Research Center of Near-Net-Shape Forming for Metallic Materials, South China University of Technology, Guangzhou, 510640 P.R. China Xiaoqiang Li, National Engineering Research Center of Near-Net-Shape Forming for Metallic Materials, South China University of Technology, Guangzhou, 510640 P.R. China Shengguan Qu, National Engineering Research Center of Near-Net-Shape Forming for Metallic Materials, South China University of Technology, Guangzhou, 510640 P.R. China Yuanyuan Li, National Engineering Research Center of Near-Net-Shape Forming for Metallic Materials, South China University of Technology, Guangzhou, 510640 P.R. China Journal Metallurgical and Materials Transactions A Online ISSN 1543-1940 Print ISSN 1073-5623

Description:    Damage tolerance (toughness and plasticity) properties of a ZrCuNiAl bulk metallic glass (BMG) are tailored through Sn alloying under ambient conditions. The result shows that the measured fracture energy is clearly correlated with the product ( R ) of Young’s modulus and averaged size of vein patterns on mode I crack surfaces of these BMGs. The implications of the current result on other BMGs are also briefly discussed, which might be useful for the evaluation of damage tolerance of tough BMGs. Content Type Journal Article Pages 1-8 DOI 10.1007/s11661-012-1453-5 Authors C. C. Yuan, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190 P.R. China X. X. Xia, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190 P.R. China K. H. Jiang, School of Mechanics, Beihang University, Beijing, P.R. China D. Q. Zhao, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190 P.R. China X. K. Xi, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190 P.R. China Journal Metallurgical and Materials Transactions A Online ISSN 1543-1940 Print ISSN 1073-5623

Description:    In this study, a comparison in the oxidation and corrosion behavior of Ni/Ni-Co aluminum and alumina-reinforced electrodeposited composites has been made. The developed coatings were characterized for the morphology, structure, microhardness, oxidation, and corrosion resistance. It was found that the incorporation of Al particles in NiCo matrix is higher (9 wt pct) compared to Ni matrix (1 wt pct). In the case of aluminum oxide particles, about 5 and 7 wt pct had been obtained in Ni and NiCo matrices respectively. The difference in the surface morphology was observed with respect to metallic (Al) and inert ceramic (Al 2 O 3 ) particle incorporation. X-ray diffraction studies showed the presence of predominant Ni (200) reflection in the coatings. Also, peaks corresponding to Al and Al 2 O 3 particles were present. The Ni/NiCo-Al coatings exhibited higher microhardness values at 1273 K (1000 °C) compared to alumina-reinforced coatings, indicating better thermal stability of the former coatings. The NiAl coating showed one and two orders of magnitude improved oxidation resistance compared to NiCoAl and Ni/NiCo-Al 2 O 3 coatings, respectively. It was observed that the Ni-Al composite coating exhibited poor corrosion resistance in 3.5 pct NaCl solution compared to the other coatings studied. Content Type Journal Article Pages 1-12 DOI 10.1007/s11661-012-1452-6 Authors Meenu Srivastava, Council of Scientific and Industrial Research, Surface Engineering Division, National Aerospace Laboratories, Bangalore, 560 017 India J. N. Balaraju, Council of Scientific and Industrial Research, Surface Engineering Division, National Aerospace Laboratories, Bangalore, 560 017 India B. Ravisankar, Department of Metallurgical and Materials Engineering, National Institute of Technology, Tiruchirappalli, 620015 TN, India V. K. William Grips, Council of Scientific and Industrial Research, Surface Engineering Division, National Aerospace Laboratories, Bangalore, 560 017 India Journal Metallurgical and Materials Transactions A Online ISSN 1543-1940 Print ISSN 1073-5623

Description:    Homo–Ge, homo–Si, and hetero–Si 0.2 Ge 0.8 alloy epitaxial layers, using molecular beam epitaxy (MBE), were grown on Ge and Si (001) substrates in order to study development of crystalline strains caused by ion bombardment during the growth of materials. Ion energies and ion/atom fluxes were used in the epitaxial growth, and significant lattice distortions along the growth direction developed. Using high-resolution X-ray diffraction (HRXRD) and high-resolution transmission electron microscopy (HRTEM), the form of distortion, caused by low-energy argon (Ar + ) and xenon (Xe + ) bombardment of the thin epitaxial films grown on the (001) substrates, were investigated. The isotropic point defects case (of spherical distortions) occurs in epitaxial thin films “as-grown” processes. The intensity distribution has two maxima, one from the distorted layer and the other from the original unaffected matrix. The significant changes in the 2θ location, peak broadening and integrated intensity from the secondary (004)* reflections were obtained as a function of aging temperatures in the grown layers. Defects-induced diffuse scattering close to and between Bragg reflections supplies information on the strain and symmetry of the distortions fields and yields the atomic structure of point defects (self-interstitial, vacancies, and small clusters). First, aging heat treatment affects the distribution of distortions obtained in local regions at the “as-grown” layer, which develops to a special topography of continued distortions at higher aging temperatures. At aging temperatures above 923 K (650 °C), this extra diffraction peak disappears. The TEM observations reveal the appearance of dislocation lines with dark and bright contrasts around them, interdislocation strain contrasts, and disordered point defects atoms in the silicon region with semicoherent interfaces. The ion bombardment-induced formations and injection of the different types of pointlike defects and defects clusters. Content Type Journal Article Category Symposium: Neutron and X-Ray Studies of Advanced Materials V Pages 1-13 DOI 10.1007/s11661-012-1448-2 Authors Paul Rozenak, Hydrogen Energy Batteries Ltd., Omer, 84965 Israel Journal Metallurgical and Materials Transactions A Online ISSN 1543-1940 Print ISSN 1073-5623

Description:    In this article, a genetic algorithm (GA) is used to predict the mechanical properties and to optimize the process conditions of Al nanocomposites. An artificial intelligence method is also implemented as an assisting tool for engineering tasks of GAs. The principle of the survival of the fittest is applied to produce successively superior approximations to a solution. A population of points at each iteration is generated. The population approaches an optimal solution. The next population by computations that involve random choices is selected. The optimal volume percentage of SiC, cooling rate, and temperature gradient are computed to be 2.84 pct, 283 K/s (10 °C/s), 1273 K/m (1000 °C/m), respectively. Content Type Journal Article Pages 1-7 DOI 10.1007/s11661-012-1339-6 Authors Ali Mazahery, Karaj Branch, Islamic Azad University, Karaj, Iran Mohsen Ostad Shabani, Karaj Branch, Islamic Azad University, Karaj, Iran Journal Metallurgical and Materials Transactions A Online ISSN 1543-1940 Print ISSN 1073-5623

Description:    We developed a novel process for foaming aluminum and its alloys without using a blowing agent. The process involves a designated apparatus in which molten aluminum and its alloys are first foamed under reduced pressure and then solidified quickly. Foaming was done for pure aluminum (99.99 pct) and AlMg5 alloy not containing stabilizing particles and AlMg5 and AlSi9Mg5 alloys containing 5 vol pct SiO 2 particles. We discuss the foaming mechanism and develop a model for estimating the porosity that can be achieved in this process. The nucleation of pores in foams is also discussed. Content Type Journal Article Pages 1-8 DOI 10.1007/s11661-012-1398-8 Authors G. S. Vinod Kumar, Technische Universität Berlin, 10623 Berlin, Germany M. Mukherjee, Department of Metallurgical and Materials Engineering, Indian Institute of Technology Madras, Chennai, India F. Garcia-Moreno, Institute of Applied Materials (Fl1), Helmholtz-Zentrum Berlin für Materialien und Energie, 14109 Berlin, Germany J. Banhart, Institute of Applied Materials (Fl1), Helmholtz-Zentrum Berlin für Materialien und Energie, 14109 Berlin, Germany Journal Metallurgical and Materials Transactions A Online ISSN 1543-1940 Print ISSN 1073-5623

Description:    The surface hardness of powder injection molded (PIM) 316L is generally low due to the inherited austenitic structure and large grains induced during high-temperature sintering. To increase the surface hardness and the wear resistance, low-temperature carburization (LTC) was applied to PIM 316L. With carburization at 773 K (500 °C) for 24 hours, the resulting hardness at the surface increases from 160 to 810 HV due to the “colossal” supersaturation of interstitial carbon and M 5 C 2 carbide, and the corrosion resistance is not deteriorated. The carburized depth is about 40 μm, and the carbon content in this layer is about 3.25 wt pct or 13.5 at. pct, which causes lattice expansion of the austenite. When the carburization temperature increases to 823 K (550 °C), or the carburization time increases to 72 hours, chromium carbides are observed and the corrosion resistance is impaired. One distinct advantage of applying LTC to PIM 316L is that no acid cleaning process is required, unlike for wrought counterparts, because of the clean surface of the sintered materials. Content Type Journal Article Pages 1-8 DOI 10.1007/s11661-012-1458-0 Authors Li-Hui Cheng, Department of Materials Science and Engineering, National Taiwan University, 1 Roosevelt Road, Sec. 4, Taipei, 106 Taiwan, ROC Kuen-Shyang Hwang, Department of Materials Science and Engineering, National Taiwan University, 1 Roosevelt Road, Sec. 4, Taipei, 106 Taiwan, ROC Journal Metallurgical and Materials Transactions A Online ISSN 1543-1940 Print ISSN 1073-5623

Description:    The investment casting process is an economic production method for engineering components in TiAl-based alloys and offers the benefits of a near net-shaped component with a good surface finish. An investigation was undertaken to develop three new face coat systems based on yttria, but with better sintering properties. These face coat systems were mainly based on an yttria-alumina-zirconia system (Y 2 O 3 -0.5 wt pct Al 2 O 3 -0.5 wt pct ZrO 2 ), an yttria-fluoride system (Y 2 O 3 -0.15 wt pct YF 3 ), and an yttria-boride system (Y 2 O 3 -0.15 wt pct B 2 O 3 ). After sintering, the chemical inertness of the face coat was first tested and analyzed using a sessile drop test through the metal wetting behavioral change for each face coat surface. Then, the interactions between the shell and metal were studied by centrifugal investment casting TiAl bars. Although the sintering aids in yttria can decrease the chemical inertness of the face coat, the thickness of the interaction layer in the casting was less than 10  μ m; therefore, these face coats still can be possible face coat materials for investment casting TiAl alloys. Content Type Journal Article Pages 1-11 DOI 10.1007/s11661-012-1455-3 Authors Xu Cheng, School of Metallurgy and Materials, The University of Birmingham, Birmingham, B15 2TT U.K. Chen Yuan, School of Metallurgy and Materials, The University of Birmingham, Birmingham, B15 2TT U.K. Nick Green, School of Metallurgy and Materials, The University of Birmingham, Birmingham, B15 2TT U.K. Paul Withey, School of Metallurgy and Materials, The University of Birmingham, Birmingham, B15 2TT U.K. Journal Metallurgical and Materials Transactions A Online ISSN 1543-1940 Print ISSN 1073-5623

Description:    The creep rates of AA1100 are measured during exposure to a variety of aggressive environments. NaCl solutions of various concentrations have no influence on the steady-state creep behavior, producing creep rates comparable to those measured in lab air at room temperature. However, after an initial incubation period of steady strain rate, a dramatic increase of strain rate is observed on exposure to HCl solutions and NaOH solutions, as well as during cathodic polarization of specimens in NaCl solutions. Creep strain produces a continuous deformation and elongation of the sample surface that is comparable to slow strain rates at crack tips thought to control the kinetics of crack growth during stress corrosion cracking (SCC). In this experiment, we separate the strain and surface deformation from the complex geometry of the crack tip to better understand the processes at work. Based on this concept, two possible explanations for the environmental influences on creep strain rates are discussed relating to the anodic dissolution of the free surface and hydrogen influences on deformation mechanisms. Consistencies of pH dependence between corrosion creep and SCC at low pH prove a creep-involved SCC mechanism, while the discrepancies between corrosion creep behavior and previous SCC results at high pH indicate a rate-limit step change in the crack propagation of the SCC process. Content Type Journal Article Category Symposium: Environmental Damage in Structural Materials under Static/Dynamic Loads at Ambient Temperature Pages 1-9 DOI 10.1007/s11661-012-1294-2 Authors Quanhe Wan, Mechanical Engineering Department, University of Rochester, Rochester, NY 14642, USA David J. Quesnel, Mechanical Engineering Department, University of Rochester, Rochester, NY 14642, USA Journal Metallurgical and Materials Transactions A Online ISSN 1543-1940 Print ISSN 1073-5623

Description:    Acoustic emission (AE) is used in this article to study melting and solidification of embedded indium particles in the size ranging from 0.2 to 3  μ m in diameter and to show that dislocation generation occurs in the aluminum matrix to accommodate a 2.5 pct volume change. The volume-averaged acoustic energy produced by indium particle melting is similar to that reported for bainite formation upon continuous cooling. A mechanism of prismatic loop generation is proposed to accommodate the volume change, and an upper limit to the geometrically necessary increase in dislocation density is calculated as 4.1 × 10 9  cm −2  for the Al-17In alloy. Thermomechanical processing is also used to change the size and distribution of the indium particles within the aluminum matrix. Dislocation generation with accompanied AE occurs when the melting indium particles are associated with grain boundaries or upon solidification where the solid-liquid interfaces act as free surfaces to facilitate dislocation generation. AE is not observed for indium particles that require super heating and exhibit elevated melting temperatures. The AE work corroborates previously proposed relaxation mechanisms from prior internal friction studies and that the superheat observed for melting of these micron-sized particles is a result of matrix constraint. Content Type Journal Article Category Symposium: Atomistic Effects in Migrating Interphase Interfaces: Recent Progress and Future Study Pages 1-12 DOI 10.1007/s11661-012-1468-y Authors Michael M. Kuba, Department of Materials Science and Engineering, Missouri University of Science and Technology, 223 McNutt Hall, 1400 N. Bishop, Rolla, MO 65409-0330, USA David C. Van Aken, Department of Materials Science and Engineering, Missouri University of Science and Technology, 223 McNutt Hall, 1400 N. Bishop, Rolla, MO 65409-0330, USA Journal Metallurgical and Materials Transactions A Online ISSN 1543-1940 Print ISSN 1073-5623

Description:    Microwave dielectric ceramics of Ba[Zn (1− x )/3 Ni x /3 Nb 2/3 ]O 3 (BZNN, x  = 0.0, 0.5, 0.6, 0.7, 0.8) were sintered at 1773 K (1500 °C) for 3 hours by the conventional solid-state reaction method. To clarify the relationship between dielectric properties and crystal structures, vibration spectra (Raman spectroscopy and Fourier transform far-infrared reflection spectroscopy (FTIR)) and X-ray diffraction (XRD) were employed to study Ba[Zn (1-x)/3 Ni x/3 Nb 2/3 ]O 3 solid solutions. Crystal structures were determined as cubic perovskite structures, and no phase transition appears in substitution of Ni 2+ to Zn 2+ ions. Raman spectroscopy was used to discuss the correlation of dielectric properties with Raman shifts and full-width at half-maximum (FWHM) values, which indicate that dielectric properties are closely related to both FWHM values and A 1g (Nb) mode shifts. FTIR spectra and imaginary parts of dielectric constants were calculated to obtain the correlation between polar phonon modes and dielectric properties with Ni 2+ concentration. Content Type Journal Article Pages 1-7 DOI 10.1007/s11661-012-1401-4 Authors Feng Shi, College of Physics and Electronics, Shandong Normal University, Jinan, 250014 People’s Republic of China Chuanling Diao, College of Physics and Electronics, Shandong Normal University, Jinan, 250014 People’s Republic of China Journal Metallurgical and Materials Transactions A Online ISSN 1543-1940 Print ISSN 1073-5623

Description:    Closely related species with different physiological tolerances and distributions make ideal systems for documenting range shifts in response to a changing climate. Mytilus edulis, M. trossulus , and M. galloprovincialis are sibling species of marine mussels with distinct biogeographical ranges that are correlated with sea surface temperatures. We determined the scope for growth of these three species at a range of temperatures to determine if energetics could predict their distributions. Scope for growth (SFG) represents energy available for growth and/or reproduction above that necessary for maintenance requirements. The SFG of M. galloprovincialis , the species known to inhabit the warmest habitats, was shifted towards warmer temperatures compared to the other two species, remaining positive until nearly 30 °C. M. edulis , a cold-temperate species, maintained a positive SFG up to 23 °C. M. trossulus, a boreal species, generally was not able to maintain a positive SFG above 17 °C. The warm end of each species’ range correlated strongly with the point at which that species’ SFG became negative in summer and fall. Energetics at cold temperatures did not predict the cold end of the species’ ranges, as there was no clear SFG advantage to explain the dominance of M. trossulus in cold habitats. As sea surface temperatures continue to warm with climate change, the energetics of these three species provide a basis for developing mechanistic models predicting future distribution and productivity changes in mussel populations. Content Type Journal Article Category Physiological ecology - Original research Pages 1-12 DOI 10.1007/s00442-012-2486-6 Authors Elizabeth K. Fly, Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA Thomas J. Hilbish, Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Phenotypic plasticity has recently been proposed to increase population viability when rapid anthropogenic environmental changes cannot be tracked by means of evolution. This assumes that environmental changes do not constrain phenotypic plasticity itself, which has rarely been examined in natural populations. In areas of climate warming, many long-distance migratory birds breed increasingly late relative to the period of peak food supply, and the temporal mismatch may constrain plastic life-history traits such as nestling growth. We combined 23 years of food availability and breeding data with a 3-year experimental manipulation of nestling growth trajectories in a Central European population of collared flycatchers ( Ficedula albicollis ) to examine the potential impact of climate-related mistimed breeding on nestling developmental plasticity. Timing of the food peak was predicted by winter climate, and the median hatching date of broods was earlier in springs with earlier food peaks. However, the adjustment of hatching date was incomplete and the population largely missed the food peak in years with very early food peaks. After imposing a temporary, experimental food shortage on nestlings, the extent of compensatory growth in body mass differed among years, and this difference was apparently related to the distance of hatching dates from the yearly food peak. Growth compensation declined with distance from the peak. These results suggest that mistimed phenology may not only create permanently adverse conditions for migratory species but it may also constrain the plastic responses of individuals to temporary disturbances. Therefore, climate change may not only favour but also restrict phenotypic plasticity. Content Type Journal Article Category Global change ecology - Original research Pages 1-13 DOI 10.1007/s00442-012-2487-5 Authors Gergely Hegyi, Behavioural Ecology Group, Department of Systematic Zoology and Ecology, Eötvös Loránd University, Pázmány Péter sétány 1/C, Budapest, 1117 Hungary Gergely Nagy, Behavioural Ecology Group, Department of Systematic Zoology and Ecology, Eötvös Loránd University, Pázmány Péter sétány 1/C, Budapest, 1117 Hungary János Török, Behavioural Ecology Group, Department of Systematic Zoology and Ecology, Eötvös Loránd University, Pázmány Péter sétány 1/C, Budapest, 1117 Hungary Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Successional changes in belowground ectomycorrhizal fungal (EMF) communities have been observed with increasing forest stand age; however, mechanisms behind this change remain unclear. It has been hypothesized that declines of inorganic nitrogen (N) and increases of organic N influence changes in EMF taxa over forest development. In a post-wildfire chronosequence of six jack pine ( Pinus banksiana ) stands ranging in age from 5 to 56 years, we investigated EMF community composition and compared shifts in taxa with detailed soluble inorganic and organic N data. Taxa were identified by internal transcribed spacer rDNA sequencing, and changes in community composition evaluated with non-metric multi-dimensional scaling (NMDS). Dissimilarities in the community data were tested for correlations with N variables. We observed a successional shift along NMDS axis 1 from such taxa as Suillus brevipes and Thelephora terrestris in sites age 5 and 11 to species of Cortinarius and Russula , among others, in the four older sites. This change was positively correlated with soluble organic N (SON) ( r 2  = 0.902, P  = 0.033) and free amino-acid N ( r 2  = 0.945, P  = 0.021), but not inorganic N. Overall, our results show a successional shift of EMF communities occurring between stand initiation and canopy closure without a change in species of the dominant plant–host, and associated with SON and free amino-acid N in soil. It is uncertain whether EMF taxa are responding to these organic N forms directly, affecting their availability, or are ultimately responding to changes in other site variables, such as belowground productivity. Content Type Journal Article Category Ecosystem ecology - Original research Pages 1-13 DOI 10.1007/s00442-012-2471-0 Authors Stephen D. LeDuc, Department of Forestry and the Ecology, Evolutionary Biology and Behavior Program, Michigan State University, 126 Natural Resources, East Lansing, MI 48824, USA Erik A. Lilleskov, U.S. Department of Agriculture Forest Service, Forestry Sciences Laboratory, 410 MacInnes Dr., Houghton, MI 49931, USA Thomas R. Horton, Department of Environmental and Forest Biology, State University of New York–College of Environmental Science and Forestry, 1 Forestry Drive, Syracuse, NY 13210, USA David E. Rothstein, Department of Forestry and the Ecology, Evolutionary Biology and Behavior Program, Michigan State University, 126 Natural Resources, East Lansing, MI 48824, USA Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    The effect of herbivory on plant performance is the subject of a large number of ecological studies, and plant responses to herbivory range from reduced reproduction to overcompensation. Because plant defenses, stored resources, and allocation demands change throughout a plant’s lifetime, it can be hypothesized the effects of herbivory also vary with development. The present work extends previous analyses to incorporate hundreds of studies in a new meta-analysis addressing this topic. Herbivores had an overall negative effect on plant growth and reproduction, and, in contrast to a previous meta-analysis, this work shows the timing of herbivory is relevant. Differences in the effects of herbivory between life stages existed for woody plant reproduction and perennial herb growth. In addition, tree and shrub growth was reduced by herbivore damage at early ontogenetic stages, and perennial herb reproduction was limited by adult stage herbivory. These results partially support the continuum of an ontogenetic response model. Finally, consideration of this synthesis in conjunction with other work led to the conclusion that different plant groups optimize their defense investments in unique ways. Slow-growing plants may strongly chemically defend young tissues, supporting the plant–age hypothesis, because early herbivory is detrimental to growth. Faster-growing herbs may invest more in antiherbivore defense when they are older, supporting the growth–differentiation balance hypothesis, because later herbivory limits their reproduction. Content Type Journal Article Category Concepts, Reviews and Syntheses Pages 1-10 DOI 10.1007/s00442-012-2470-1 Authors Tara Joy Massad, Max Planck Institute for Biogeochemistry, Beutenberg Campus, Hans-Knöll-Str. 10, 07745 Jena, Germany Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    The solidification structures of Al-Cu 206 cast alloys at a high iron level of 0.5 pct were systematically studied by means of differential scanning calorimetry, electron backscattered diffraction, and transmission electron microscopy. The full solidification sequences of the 206 cast alloys at 0.5 pct Fe were established. The influences of both alloy composition ( i.e. , Si and Mn contents) and cooling rate on the formation and phase selection of the iron-rich intermetallics have been systematically explored. At a cooling rate of 12 K/min, it was found that one of the three iron-rich phases, i.e. , Chinese script Al m (FeMn) and α-Fe, or platelet Al 3 (FeMn), may precipitate as the dominant iron-rich intermetallic, depending on Si and Mn contents. However, the dominant Chinese script iron-rich intermetallics, Al m (FeMn) and/or α-Fe, can be fully obtained for the 206 Al-Cu cast alloys at 0.5 pct Fe above a threshold cooling rate that can easily be obtained in normal industrial casting conditions, indicating that there is a significant potential of designing and developing new 206 Al-Cu cast alloys with a high tolerant iron content. Content Type Journal Article Pages 1-14 DOI 10.1007/s11661-012-1419-7 Authors K. Liu, University of Québec at Chicoutimi, Chicoutimi, QC G7H 2B1, Canada X. Cao, University of Québec at Chicoutimi, Chicoutimi, QC G7H 2B1, Canada X.-G. Chen, University of Québec at Chicoutimi, Chicoutimi, QC G7H 2B1, Canada Journal Metallurgical and Materials Transactions A Online ISSN 1543-1940 Print ISSN 1073-5623

Description:    The flow behavior and recrystallization response of a 9310 steel alloy deformed in the ferrite temperature range were studied in this work. Samples were compressed under various conditions of strain (0.6, 0.8 and multi-axial), strain rate (10 −4  seconds −1 to 10 −1  seconds −1 ) and temperature [811 K to 1033 K (538 °C to 760 °C)] using a Gleeble thermo-mechanical simulator. Deformation was characterized by both qualitative and quantitative means, using standard microscopy, electron backscatter diffraction (EBSD) analysis and flow stress modeling. The results indicate that deformation is primarily accommodated through dynamic recovery in sub-grain formation. EBSD analysis shows a continuous increase in sub-grain boundary misorientation with increasing strain, ultimately producing recrystallized grains from the sub-grains at high strains. This suggests that a sub-grain rotation recrystallization mechanism predominates in this temperature range. Analyses of the results reveal a decreasing mean dynamically recrystallized grain size with increasing Zener-Hollomon parameter, and an increasing recrystallized fraction with increasing strain. Content Type Journal Article Pages 1-15 DOI 10.1007/s11661-012-1381-4 Authors David Snyder, Illinois Institute of Technology, 10 W. 32nd St., Chicago, IL 60616, USA Edward Y. Chen, Transition45 Technologies, Inc., 1739 N. Case St., Orange, CA 92865, USA Charlie C. Chen, Transition45 Technologies, Inc., 1739 N. Case St., Orange, CA 92865, USA Sammy Tin, Illinois Institute of Technology, 10 W. 32nd St., Chicago, IL 60616, USA Journal Metallurgical and Materials Transactions A Online ISSN 1543-1940 Print ISSN 1073-5623

Description:    The Mg 17 Ni 1.5 Ce 0.5 hydrogen storage composites with different contents of graphite were prepared by a new method of mechanical milling and subsequent microwave sintering. The small particle size (~25  μ m) and the low echo ratio of power indicate that graphite plays an important role not only as a lubricant during mechanical milling but also as a supplementary heating material during microwave sintering. As a catalyst in the hydriding/dehydriding (H/D) reaction, graphite also improved the hydrogen storage properties of the composites. The hydrogen absorption and desorption capacities of Mg 17 Ni 1.5 Ce 0.5 with 5 wt pct graphite were 5.34 and 5.30 wt pct H 2 at 573 K (300 °C), its onset temperature of dehydriding reaction was 511 K (238 °C), and its activation energies of H/D reaction were 40.9 and 54.5 kJ/mol H 2 , respectively. The kinetic mechanisms of the H/D reaction are also discussed. Content Type Journal Article Category Symposium: Neutron and X-Ray Studies of Advanced Materials V Pages 1-10 DOI 10.1007/s11661-012-1301-7 Authors Jie Meng, Shanghai Key Laboratory of Modern Metallurgy & Materials Processing, Shanghai University, Shanghai, 200072 People’s Republic of China Xun-Li Wang, Neutron Scattering Science Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA Kuo-Chih Chou, Shanghai Key Laboratory of Modern Metallurgy & Materials Processing, Shanghai University, Shanghai, 200072 People’s Republic of China Qian Li, Shanghai Key Laboratory of Modern Metallurgy & Materials Processing, Shanghai University, Shanghai, 200072 People’s Republic of China Journal Metallurgical and Materials Transactions A Online ISSN 1543-1940 Print ISSN 1073-5623

Description:    The evolution of titanium powders in the pure aluminum melt at a lower temperature was studied in our research. The process involved some titanium powders being added into the pure aluminum melt at 1003 K (730 °C), and then the melt was cast into an ingot after 5 minutes. A reaction layer composed of some loose Al 3 Ti particles was formed on the solid Ti surface due to the reactive diffusion between titanium and aluminum. In-situ blocky Al 3 Ti particles smaller than 5  μ m were produced in the aluminum matrix. A reaction-peeling model was suggested to illustrate the formation mechanism of Al 3 Ti particles, and a simple approach for fabricating in-situ Al 3 Ti/Al-alloy composites was proposed as well. Content Type Journal Article Category Communication Pages 1-4 DOI 10.1007/s11661-012-1326-y Authors Z. W. Liu, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai, 200240 P.R. China Q. Han, Department of Mechanical Engineering Technology, Purdue University, West Lafayette, IN 47906, USA J. G. Li, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai, 200240 P.R. China Journal Metallurgical and Materials Transactions A Online ISSN 1543-1940 Print ISSN 1073-5623

Description:    The diffusionless growth model of bainite formation was included in an international consensus in 1912 that all transformation products of austenite form by an initial transformation to martensite. The introduction of isothermal treatment revealed that all the products form directly. However, for bainite, the idea of some relation to martensite survived and developed into the diffusionless paradigm. Zener introduced the T o concept for predicting the start temperature of lower bainite, but also described diffusional growth of upper bainite. The present description of the diffusionless growth model is now examined and criticized. Content Type Journal Article Pages 1-9 DOI 10.1007/s11661-012-1263-9 Authors M. Hillert, Department of Materials Science and Engineering, KTH Royal Institute of Technology, 10044 Stockholm, Sweden A. Borgenstam, Department of Materials Science and Engineering, KTH Royal Institute of Technology, 10044 Stockholm, Sweden Journal Metallurgical and Materials Transactions A Online ISSN 1543-1940 Print ISSN 1073-5623

Description:    A developed Ti-35 pct Nb-2.5 pct Sn (wt pct) alloy was synthesized by mechanical alloying using high-energy ball-milled powders, and the powder consolidation was done by pulsed current activated sintering (PCAS). The starting powder materials were mixed for 24 hours and then milled by high-energy ball milling (HEBM) for 1, 4, and 12 hours. The bulk solid samples were fabricated by PCAS at 1073 K to 1373 K (800 °C to 1100 °C) for a short time, followed by rapid cooling to 773 K (500 °C). The relative density of the sintered samples was about 93 pct. The Ti was completely transformed from α to β -Ti phase after milling for 12 hours in powder state, and the specimen sintered at 1546 K (1273 °C) was almost transformed to β -Ti phase. The homogeneity of the sintered specimen increased with increasing milling time and sintering temperature, as did its hardness, reaching 400 HV after 12 hours of milling. The Young’s modulus was almost constant for all sintered Ti-35 pct Nb-2.5 pct Sn specimens at different milling times. The Young’s modulus was low (63.55 to 65.3 GPa) compared to that of the standard alloy of Ti-6Al-4V (100 GPa). The wear resistance of the sintered specimen increased with increasing milling time. The 12-hour milled powder exhibited the best wear resistance. Content Type Journal Article Pages 1-9 DOI 10.1007/s11661-012-1298-y Authors Abdel-Nasser Omran, Mining and Metallurgical Department, Faculty of Engineering, Al-Azhar University, Qena, Egypt Kee-Do Woo, Division of Advanced Materials Engineering & RCAMD, Chonbuk National University, Jeonju, 561-756 Korea Hyun Bom Lee, Mg Flat Product Process Engineering Team, POSCO, Jeonnam, 540-856 Korea Journal Metallurgical and Materials Transactions A Online ISSN 1543-1940 Print ISSN 1073-5623

Description:    A two-camera Particle Image Velocimetry (PIV) technique is applied to study the flow pattern and the equiaxed crystal motion during an equiaxed/columnar solidification process of Ammonium Chloride in a die cast cell. This technique is able to measure simultaneously the liquid and the equiaxed grain velocity pattern as already shown in Part I of this paper. The interaction between the equiaxed grains and the melt flow was explored by means of relative velocities. In single isolated configurations, the settling velocity of equiaxed crystal was found to be 41 times smaller than spheres of equivalent size. The coupling between the fluid flow and the equiaxed crystals was found to be important in areas of high crystal density. Chaotic and turbulent behaviors are found to be damped in regions of high equiaxed crystal density. Content Type Journal Article Pages 1-8 DOI 10.1007/s11661-012-1415-y Authors Abdellah Kharicha, Department of Metallurgy, University of Leoben, Leoben, Austria Mihaela Stefan-Kharicha, Department of Metallurgy, University of Leoben, Leoben, Austria Andreas Ludwig, Department of Metallurgy, University of Leoben, Leoben, Austria Menghuai Wu, Department of Metallurgy, University of Leoben, Leoben, Austria Journal Metallurgical and Materials Transactions A Online ISSN 1543-1940 Print ISSN 1073-5623

Description:    The effect of C fraction (C/N) on stacking fault energy (SFE) of austenitic Fe-18Cr-10Mn steels with a fixed amount of C + N (0.6 wt pct) was investigated by means of neutron diffraction and transmission electron microscopy (TEM). The SFE were evaluated by the Rietveld whole-profile fitting combined with the double-Voigt size-strain analysis for neutron diffraction profiles using neutron diffraction. The measured SFE showed distinguishable difference and were well correlated with the change in deformation microstructure. Three-dimensional linear regression analyses yielded the relation reflecting the contribution of both C + N and C/N: SFE (mJ/m 2 ) = –5.97 + 39.94(wt pct C + N) + 3.81(C/N). As C fraction increased, the strain-induced γ → ε martensitic transformation was suppressed, and deformation twinning became the primary mode of plastic deformation. Content Type Journal Article Category Communication Pages 1-5 DOI 10.1007/s11661-012-1423-y Authors Tae-Ho Lee, Ferroy Alloy Department, Korea Institute of Materials Science, Changwon, 642-831 South Korea Heon-Young Ha, Ferroy Alloy Department, Korea Institute of Materials Science, Changwon, 642-831 South Korea Byoungchul Hwang, Ferroy Alloy Department, Korea Institute of Materials Science, Changwon, 642-831 South Korea Sung-Joon Kim, Graduate Institute of Ferrous Technology, Pohang University of Science & Technology, Pohang, 790-784 South Korea Eunjoo Shin, Neutron Physics Department, Korea Atomic Energy Research Institute, Daejeon, 305-600 South Korea Journal Metallurgical and Materials Transactions A Online ISSN 1543-1940 Print ISSN 1073-5623

Description:    A dual phase particle image velocimetry technique is applied to study the flow pattern during a combined equiaxed-columnar solidification process. This technique is able to measure simultaneously the liquid and the equiaxed grain velocity pattern within an academic Ammonium Chloride water ingot. After the formation of a steady convection pattern, solutal buoyancy together with falling crystals destabilize and break the steady convection flow into multiple chaotic cells. In the beginning of the solidification process, the flow transitioned from 2D to a 3D turbulent regime. The kinetic energy for the flow was calculated during the solidification process. Content Type Journal Article Pages 1-11 DOI 10.1007/s11661-012-1414-z Authors Abdellah Kharicha, Department of Metallurgy, University of Leoben, Leoben, Austria Mihaela Stefan-Kharicha, Department of Metallurgy, University of Leoben, Leoben, Austria Andreas Ludwig, Department of Metallurgy, University of Leoben, Leoben, Austria Menghuai Wu, Department of Metallurgy, University of Leoben, Leoben, Austria Journal Metallurgical and Materials Transactions A Online ISSN 1543-1940 Print ISSN 1073-5623

Description:    The precipitates in as-cast and heat-treated biomedical Co-28Cr-6Mo-(0 to 0.35)C-(0.15 to 0.25)N alloys (mass pct) were investigated. Heat treatment was carried out at temperatures of 1473 K to 1573 K (1200 °C to 1300 °C) for holding periods of 0 to 43.2 ks. In the as-cast and heat-treated Co-Cr-Mo-N alloys, no precipitates were detected; nitrogen effectively inhibited the formation of the σ-phase and stabilized the face-centered cubic (fcc) metallic γ-phase. The precipitates observed in the as-cast and heat-treated Co-Cr-Mo-C-N alloys were of the M 23 X 6 type, M 2 X type, π-phase (M 2 T 3 X type with a β-Mn structure), and η-phase (M 6 X-M 12 X type). Complete precipitate dissolution was detected in the alloys with carbon contents of less than 0.3 mass pct regardless of the nitrogen content. The main precipitates were of the M 2 X and M 23 X 6 types after heat treatment for 1.8 to 43.2 ks. The π-phase precipitate was detected in the early stage of heat treatment at high temperatures. The formation of the M 2 X-type precipitate was enhanced by the addition of nitrogen, although the constitution of the precipitates depended on the balance between the nitrogen and carbon contents and the heat-treatment conditions. Content Type Journal Article Pages 1-10 DOI 10.1007/s11661-012-1399-7 Authors Shingo Mineta, Department of Materials Processing, Graduate School of Engineering, Tohoku University, 6-6-02, Aza Aoba, Aramaki, Aoba-ku, Sendai, 980-8579 Japan Alfirano, Department of Materials Processing, Graduate School of Engineering, Tohoku University, 6-6-02, Aza Aoba, Aramaki, Aoba-ku, Sendai, 980-8579 Japan Shigenobu Namba, Materials Research Laboratory, Kobe Steel, Ltd., Kobe, 651-2271 Japan Takashi Yoneda, Yoneda Advanced Casting Co., Ltd., Takaoka, 933-0951 Japan Kyosuke Ueda, Department of Materials Processing, Graduate School of Engineering, Tohoku University, 6-6-02, Aza Aoba, Aramaki, Aoba-ku, Sendai, 980-8579 Japan Takayuki Narushima, Department of Materials Processing, Graduate School of Engineering, Tohoku University, 6-6-02, Aza Aoba, Aramaki, Aoba-ku, Sendai, 980-8579 Japan Journal Metallurgical and Materials Transactions A Online ISSN 1543-1940 Print ISSN 1073-5623

Description:    Copper precipitation has been studied by thermoelectric power measurements in a high strength interstitial free steel processed under various conditions like batch annealing (BA) (4 hours at 973 K (700 °C)), continuous annealing (CA) (1 minute at 1093 K (820 °C)) and full annealing (FA) (2 hours at 1173 K (900 °C)). The results show that the kinetics of copper precipitation depend on the annealing pre-treatments which influence the amount of copper in solid solution before aging. Extensive copper precipitation associated with a marked increase in hardness was observed in the CA and FA material aged between 773 K and 873 K (500 °C and 600 °C), however, this precipitation was not detected when the steel was subjected to BA before aging. Content Type Journal Article Pages 1-15 DOI 10.1007/s11661-012-1386-z Authors Radhakanta Rana, Institut für Eisenhüttenkunde, RWTH Aachen, Intzestraße 1, Aachen, 52072 Germany Véronique Massardier, Université de Lyon, CNRS, INSA-Lyon, MATEIS UMR5510, 69621 Villeurbanne, France Shiv Brat Singh, Department of Metallurgical and Materials Engineering, Indian Institute of Technology, Kharagpur, Kharagpur, 721302 India Omkar Nath Mohanty, Department of Metallurgical and Materials Engineering, Indian Institute of Technology, Kharagpur, Kharagpur, 721302 India Journal Metallurgical and Materials Transactions A Online ISSN 1543-1940 Print ISSN 1073-5623

Description:    We have previously reported that ultrafine-grained (UFG) microstructures can be obtained in a Co-29Cr-6Mo (wt pct) alloy by utilizing dynamic recrystallization (DRX) that occurs during conventional hot deformation (Yamanaka et al .: Metall. Mater. Trans. A , 2009, vol. 40A, pp. 1980−94). The present study investigates the novel DRX mechanism of this alloy in detail. The microstructure evolution during hot deformation under relatively high Zener–Hollomon ( Z ) parameter conditions for which ultrafine grains can develop was systematically investigated by electron backscatter diffraction (EBSD) and transmission electron microscopy. This alloy exhibited a different flow stress behavior and microstructural development from conventional DRX mechanisms. The deformation microstructure contained a large number of stacking faults, which implies that planar dislocation slip is the primary deformation mechanism in the hot deformation of the Co-29Cr-6Mo alloy due to its abnormally low stacking fault energy (SFE) at elevated temperatures. Inhomogeneities in local strain distributions induced by planar slip will enhance grain subdivision by geometrically necessary (GN) dislocation boundaries. Deformation twinning may also contribute to grain refinement. The DRX mechanism operating in the Co-29Cr-6Mo alloy is discussed by considering the relationships between anomalous dislocation structures, flow stress behavior, texture development, and nucleation behavior. Content Type Journal Article Pages 1-13 DOI 10.1007/s11661-012-1303-5 Authors Kenta Yamanaka, Institute for Materials Research, Tohoku University, Sendai, 980-8577 Japan Manami Mori, Institute for Materials Research, Tohoku University, Sendai, 980-8577 Japan Akihiko Chiba, Institute for Materials Research, Tohoku University, Sendai, 980-8577 Japan Journal Metallurgical and Materials Transactions A Online ISSN 1543-1940 Print ISSN 1073-5623

Description:    Microstructural evolution taking place during equal-channel angular pressing was studied in a commercial Al-6Mg-0.3Sc alloy at 523 K (250 °C) (~0.5 T m ). The structural changes are mainly associated with development of microshear bands (MSBs) that are continuously formed by strain accumulation and microstructural heterogeneities in each pass, which result in fragmentation of coarse original grains. New ultrafine grains (UFGs) with moderate-to-high angle boundary misorientations are concurrently evolved in the interiors of MSBs accompanied by rigid body rotation at medium-to-large strains. Such strain-induced grain refinement process occurs very slowly and incompletely in the present heavily alloyed Al alloy, leading to formation of a mixed microstructure, i.e. , the UFGs in colony and some weakly misoriented fragments of original grains. The microstructure evolved at ε  ≈ 12 is characterized by a bimodal crystallite size distribution with two peaks at d 1  ≈ 0.2 to 0.3  μ m and d 2  ≈ 0.6 to 0.7  μ m, and the fraction of high angle boundaries of about 0.35 ± 0.05. The main factors promoting dynamic formation of UFGs and the effects of thermal processes on it during severe plastic deformation are discussed in detail. Content Type Journal Article Pages 1-14 DOI 10.1007/s11661-012-1438-4 Authors Oleg Sitdikov, Institute for Metals Superplasticity Problems, Russian Academy of Sciences, Khalturina 39, Ufa, 450001 Russia Elena Avtokratova, Institute for Metals Superplasticity Problems, Russian Academy of Sciences, Khalturina 39, Ufa, 450001 Russia Taku Sakai, UEC Tokyo (the University of Electro-Communications), Chofu, Tokyo 182-8585, Japan Kaneaki Tsuzaki, National Institute for Materials Science, Tsukuba, 305-0047 Japan Journal Metallurgical and Materials Transactions A Online ISSN 1543-1940 Print ISSN 1073-5623

Description:    The thermal conductivity of some common and experimental high pressure diecasting (HPDC) Al-Si-Cu alloys is evaluated. It is shown that the thermal conductivity of some compositions may be increased by more than 60 pct by utilizing T7 heat treatments. This may have substantial performance and cost benefits for applications where thermal management is a key design parameter. Content Type Journal Article Pages 1-13 DOI 10.1007/s11661-012-1443-7 Authors Roger N. Lumley, CSIRO Future Manufacturing Flagship, Private Bag 33, Clayton South MDC, VIC 3169, Australia Natalia Deeva, CSIRO Process Science and Engineering, Clayton, VIC 3169, Australia Robert Larsen, TPRL, Inc., 3080 Kent Ave., West Lafayette, IN 47906, USA Jozef Gembarovic, TA Instruments Corp., 159 Lukens Drive, New Castle, DE 19720, USA Joe Freeman, TPRL, Inc., 3080 Kent Ave., West Lafayette, IN 47906, USA Journal Metallurgical and Materials Transactions A Online ISSN 1543-1940 Print ISSN 1073-5623

Description:    Although many species may be vulnerable to changes in climate, forecasting species-level responses can be challenging given the array of physiological, behavioral, and demographic attributes that might be affected. One strategy to improve forecasts is to evaluate how species responded to climatic variation in the past. We used 22 years of capture-recapture data for Sonoran desert tortoises ( Gopherus morafkai ) collected from 15 locations across their geographic range in Arizona to evaluate how environmental factors affected spatial and temporal variation in survival. Although rates of annual survival were generally high ( $$ \overset{\lower0.5em\hbox{$\smash{\scriptscriptstyle\frown}$}}{\Upphi } $$  = 0.92), survival of adults decreased with drought severity, especially in portions of their range that were most arid and nearest to cities. In three locations where large numbers of carcasses from marked tortoises were recovered, survival of adults was markedly lower during periods of severe drought ( $$ \overset{\lower0.5em\hbox{$\smash{\scriptscriptstyle\frown}$}}{\Upphi } $$  = 0.77–0.81) compared to all other periods ( $$ \overset{\lower0.5em\hbox{$\smash{\scriptscriptstyle\frown}$}}{\Upphi } $$  = 0.93–0.98). Assuming continued levels of dependency of humans on fossil fuels, survival of adult tortoises is predicted to decrease by an average of 3 % during 2035–2060 relative to survival during 1987–2008 in 14 of the 15 populations we studied. This decrease could reduce persistence of tortoise populations, especially in arid portions of their range. Temporal and spatial variation in drought conditions are important determinants of survival in adult desert tortoises. Content Type Journal Article Category Population ecology - Original research Pages 1-10 DOI 10.1007/s00442-012-2464-z Authors Erin R. Zylstra, School of Natural Resources and the Environment, University of Arizona, 325 Biological Sciences East, Tucson, AZ 85721, USA Robert J. Steidl, School of Natural Resources and the Environment, University of Arizona, 325 Biological Sciences East, Tucson, AZ 85721, USA Cristina A. Jones, Arizona Game and Fish Department, Nongame Branch, 5000 West Carefree Highway, Phoenix, AZ 85086, USA Roy C. Averill-Murray, Desert Tortoise Recovery Office, U.S. Fish and Wildlife Service, 1340 Financial Boulevard, #234, Reno, NV 89502, USA Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Conservation of migratory wildlife requires knowledge of migratory connectivity between breeding and non-breeding locations. Stable isotopes in combination with geographical isotopic patterns (isoscapes) can provide inferences about migratory connectivity. This study examines whether such an approach can be used to infer wintering areas in sub-Saharan Africa, where we lack such knowledge for many species, but where this method has not been used widely. We measured δ 2 H, δ 13 C and δ 15 N in winter-grown feathers of a breeding Swiss and Spanish population of European hoopoe Upupa epops —a typical Palaearctic-Afrotropical migrant. δ 2 H values predicted that ~70 % of the hoopoes spent the non-breeding season in the western portion of their potential winter range. This was corroborated by a shallow east–west gradient in feather- δ 2 H values of museum specimens from known African origin across the potential winter range and by the recovery of Swiss hoopoes marked with geolocators. Hoopoes categorized as from eastern versus western regions of the wintering range were further delineated spatially using feather δ 13 C and δ 15 N. δ 15 N showed no trend, whereas adults were more enriched in 13 C in the western portion of the range, with eastern adults being in addition more depleted in 13 C than eastern juveniles. This suggests that eastern juveniles may have occupied more xeric habitats than sympatric adults. We demonstrated that stable isotopes, especially δ 2 H, could only very roughly delineate the winter distribution of a trans-Saharan Palaearctic migrant restricted primarily to the Sahelian and savanna belt south of the Sahara. Further refinements of precipitation isoscapes for Africa as well the development of isoscapes for δ 13 C and δ 15 N may improve assignment of this and other migrants. Content Type Journal Article Category Conservation ecology - Original research Pages 1-10 DOI 10.1007/s00442-012-2418-5 Authors Thomas S. Reichlin, Swiss Ornithological Institute, Seerose 1, 6204 Sempach, Switzerland Keith A. Hobson, Environment Canada, 11 Innovation Blvd., Saskatoon, SK S7N 3H5, Canada Steven L. Van Wilgenburg, Environment Canada, 11 Innovation Blvd., Saskatoon, SK S7N 3H5, Canada Michael Schaub, Swiss Ornithological Institute, Seerose 1, 6204 Sempach, Switzerland Leonard I. Wassenaar, Environment Canada, 11 Innovation Blvd., Saskatoon, SK S7N 3H5, Canada Manuel Martín-Vivaldi, Departamento de Biologia Animal, Facultad de Ciencias, Universidad de Granada, Campus de Fuentenueva s/n, 18071 Granada, Spain Raphaël Arlettaz, Swiss Ornithological Institute, Seerose 1, 6204 Sempach, Switzerland Lukas Jenni, Swiss Ornithological Institute, Seerose 1, 6204 Sempach, Switzerland Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    The rapid life cycles of freshwater algae are hypothesized to suppress selection for chemical defenses against herbivores, but this notion remains untested. Investigations of chemical defenses are rare for freshwater macrophytes and absent for freshwater red algae. We used crayfish to assess the palatability of five freshwater red algae relative to a palatable green alga and a chemically defended aquatic moss. We then assessed the roles of structural, nutritional, and chemical traits in reducing palatability. Both native and non-native crayfish preferred the green alga Cladophora glomerata to four of the five red algae. Batrachospermum helminthosum , Kumanoa holtonii , and Tuomeya americana employed activated chemical defenses that suppressed feeding by 30–60 % following damage to algal tissues. Paralemanea annulata was defended by its cartilaginous structure, while Boldia erythrosiphon was palatable. Activated defenses are thought to reduce ecological costs by expressing potent defenses only when actually needed; thus, activation might be favored in freshwater red algae whose short-lived gametophytes must grow and reproduce rapidly over a brief growing season. The frequency of activated chemical defenses found here (three of five species) is 3–20× higher than for surveys of marine algae or aquatic vascular plants. If typical for freshwater red algae, this suggests that (1) their chemical defenses may go undetected if chemical activation is not considered and (2) herbivory has been an important selective force in the evolution of freshwater Rhodophyta. Investigations of defenses in freshwater rhodophytes contribute to among-system comparisons and provide insights into the generality of plant–herbivore interactions and their evolution. Content Type Journal Article Category Plant-animal interactions - Original research Pages 1-13 DOI 10.1007/s00442-012-2455-0 Authors Keri M. Goodman, School of Biology, Georgia Institute of Technology, Atlanta, GA 30332, USA Mark E. Hay, School of Biology, Georgia Institute of Technology, Atlanta, GA 30332, USA Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Disturbances in semiarid environments have revealed a strong connection between water, salt and vegetation dynamics highlighting how the alteration of water fluxes can drive salt redistribution process and long-term environmental degradation. Here, we explore to what extent the reciprocal effect, that of salt redistribution on water fluxes, may play a role in dictating environmental changes following disturbance in dry woodlands. We assessed salt and water dynamics comparing soil-solution electrical conductivity, chloride concentration, soil water content (SWC) and soil matric and osmotic water potential (Ψ m , Ψ os ) between disturbed and undisturbed areas. A large pool of salts and chlorides present in undisturbed areas was absent in disturbed plots, suggesting deep leaching. Unexpectedly, this was associated with slight but consistently lower SWC in disturbed versus undisturbed situations during two growing seasons. The apparent paradox of increased leaching but diminishing SWC after disturbance can be explained by the effect of native salt lowering Ψ os enough to prevent full soil drying. Under disturbed conditions, the onset of deep drainage and salt leaching would raise Ψ os allowing a decline of Ψ m and SWC. Soil water storage seems to be modulated by the presence (under natural conditions) and partial leaching (following selective shrub disturbance) of large salt pools. This counterintuitive effect of disturbances may be important in semiarid regions where deep soil salt accumulation is a common feature. Our results highlight the importance of water–salt–vegetation coupling for the understanding and management of these systems. Content Type Journal Article Category Ecosystem ecology - Original research Pages 1-10 DOI 10.1007/s00442-012-2457-y Authors Victoria A. Marchesini, IFEVA-CONICET/Facultad de Agronomía, Universidad de Buenos Aires, Av. San Martín 4453, C1417DSE Buenos Aires, Argentina R. J. Fernández, IFEVA-CONICET/Facultad de Agronomía, Universidad de Buenos Aires, Av. San Martín 4453, C1417DSE Buenos Aires, Argentina E. G. Jobbágy, Grupo de Estudios Ambientales, IMASL-CONICET and Universidad de San Luis, San Luis, Argentina Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Carrion provides a resource for a subset of animal species that deliver a critical ecosystem service by consuming dead animal matter and recycling its nutrients. A growing number of studies have also shown various effects of carrion on different plant and microbial communities. However, there has been no review of these studies to bring this information together and identify priority areas for future research. We review carrion ecology studies from the last two decades and summarise the range of spatial and temporal effects of carrion on soil nutrients, microbes, plants, arthropods, and vertebrates. We identify key knowledge gaps in carrion ecology, and discuss how closing these gaps can be achieved by focusing future research on the (1) different kinds of carrion resources, (2) interactions between different components of the carrion community, (3) the ways that ecosystem context can moderate carrion effects, and (4) considerations for carrion management. To guide this research, we outline a framework that builds on the ‘ephemeral resource patch’ concept, and helps to structure research questions that link localised effects of carrion with their consequences at landscape scales. This will enable improved characterisation of carrion as a unique resource pool, provide answers for land managers in a position to influence carrion availability, and establish the ways that carrion affects the dynamics of species diversity and ecological processes within landscapes. Content Type Journal Article Category Concepts, Reviews and Syntheses Pages 1-12 DOI 10.1007/s00442-012-2460-3 Authors Philip S. Barton, Fenner School of Environment and Society, The Australian National University, Canberra, ACT 0200, Australia Saul A. Cunningham, CSIRO Ecosystem Sciences, Canberra, ACT 2601, Australia David B. Lindenmayer, Fenner School of Environment and Society, The Australian National University, Canberra, ACT 0200, Australia Adrian D. Manning, Fenner School of Environment and Society, The Australian National University, Canberra, ACT 0200, Australia Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    The importance of the thermal environment for ectotherms and its relationship with thermal physiology and ecology is widely recognized. Several models have been proposed to explain the evolution of the thermal biology of ectotherms, but experimental studies have provided mixed support. Lizards from the Liolaemus goetschi group can be found along a wide latitudinal range across Argentina. The group is monophyletic and widely distributed, and therefore provides excellent opportunities to study the evolution of thermal biology. We studied thermal variables of 13 species of the L. goetschi group, in order to answer three questions. First, are aspects of the thermal biology of the L. goetschi group modelled by the environment or are they evolutionarily conservative? Second, have thermal characteristics of these animals co-evolved? And third, how do the patterns of co-evolution observed within the L. goetschi group compare to those in a taxonomically wider selection of species of Liolaemus ? We collected data on 13 focal species and used species information of Liolaemus lizards available in the literature and additional data obtained by the authors. We tackled these questions using both conventional and phylogenetically based analyses. Our results show that lizards from the L. goetschi group and the genus Liolaemus in general vary in critical thermal minimum in relation to mean air temperature, and particularly the L. goetschi group shows that air temperature is associated with critical thermal range, as well as with body temperature. Although the effect of phylogeny cannot be ignored, our results indicate that these thermal biology aspects are modelled by cold environments of Patagonia, while other aspects (preferred body temperature and critical thermal maximum) are more conservative. We found evidence of co-evolutionary patterns between critical thermal minimum and preferred body temperature at both phylogenetic scales (the L. goetschi group and the extended sample of 68 Liolaemus species). Content Type Journal Article Category Physiological ecology - Original research Pages 1-16 DOI 10.1007/s00442-012-2447-0 Authors Débora Lina Moreno Azócar, Laboratory of Functional Morphology, University of Antwerp, Antwerp, Belgium Bieke Vanhooydonck, Laboratory of Functional Morphology, University of Antwerp, Antwerp, Belgium Marcelo F. Bonino, Instituto de Investigaciones en Biodiversidad y Medioambiente (INIBIOMA), CONICET-UNCOMA, Quintral 1250, Bariloche, 8400 Río Negro, Argentina M. Gabriela Perotti, Instituto de Investigaciones en Biodiversidad y Medioambiente (INIBIOMA), CONICET-UNCOMA, Quintral 1250, Bariloche, 8400 Río Negro, Argentina Cristian S. Abdala, Facultad de Ciencias Naturales e I. M. Lillo (UNT), CONICET-Instituto de Herpetología (FML), Tucumán, Argentina James A. Schulte, Department of Biology, Clarkson University, Potsdam, NY, USA Félix B. Cruz, Instituto de Investigaciones en Biodiversidad y Medioambiente (INIBIOMA), CONICET-UNCOMA, Quintral 1250, Bariloche, 8400 Río Negro, Argentina Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    The microstructure evolution of 25Cr-35Ni-1Mo radiant tubes was investigated after approximately two years of service in a continuous annealing furnace. The inner and outer tube walls were exposed to N 2 -containing combustion environment and protective atmosphere, respectively. The decarburization feature analysis indicated that carbon content decreased toward the tube surface. However, precipitates at the inner and outer walls were coarser, their content increased and the microhardness value also increased compared to that in the central area. X-ray diffraction illustrated that M 2 (C,N) and M 6 (C,N) were the dominant carbide at the inner and outer walls, and precipitates in the central area were mainly M 23 C 6  and M 6 (C,N) phases. The results were assumed to be associated with the nitridation phenomenon that occurred in the N 2 -containing environment at elevated temperatures. Content Type Journal Article Pages 1-7 DOI 10.1007/s11661-012-1302-6 Authors Zhichao Zhu, School of Material Science and Engineering, Dalian University of Technology, Dalian, 116085 People’s Republic of China Congqian Cheng, School of Material Science and Engineering, Dalian University of Technology, Dalian, 116085 People’s Republic of China Chunhui Liu, School of Material Science and Engineering, Dalian University of Technology, Dalian, 116085 People’s Republic of China Jie Zhao, School of Material Science and Engineering, Dalian University of Technology, Dalian, 116085 People’s Republic of China Journal Metallurgical and Materials Transactions A Online ISSN 1543-1940 Print ISSN 1073-5623

Description:    The theory of cannibal dynamics predicts a link between population dynamics and individual life history. In particular, increased individual growth has, in both modeling and empirical studies, been shown to result from a destabilization of population dynamics. We used data from a long-term study of the dynamics of two leech ( Erpobdella octoculata ) populations to test the hypothesis that maximum size should be higher in a cycling population; one of the study populations exhibited a delayed feedback cycle while the other population showed no sign of cyclicity. A hump-shaped relationship between individual mass of 1-year-old leeches and offspring density the previous year was present in both populations. As predicted from the theory, the maximum mass of individuals was much larger in the fluctuating population. In contrast to predictions, the higher growth rate was not related to energy extraction from cannibalism. Instead, the higher individual mass is suggested to be due to increased availability of resources due to a niche widening with increased individual body mass. The larger individual mass in the fluctuating population was related to a stronger correlation between the densities of 1-year-old individuals and 2-year-old individuals the following year in this population. Although cannibalism was the major mechanism regulating population dynamics, its importance was negligible in terms of providing cannibalizing individuals with energy subsequently increasing their fecundity. Instead, the study identifies a need for theoretical and empirical studies on the largely unstudied interplay between ontogenetic niche shifts and cannibalistic population dynamics. Content Type Journal Article Category Population ecology - Original research Pages 1-9 DOI 10.1007/s00442-012-2468-8 Authors Lennart Persson, Department of Ecology and Environmental Science, Umeå University, 90187 Umeå, Sweden J. Malcolm Elliott, Freshwater Biological Association, The Ferry Landing, Far Sawrey, Ambleside, Cumbria LA22 0LP, UK Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549