ALBERT

Description:    The residual stress relaxation of the shot peened layer on the SiCw/Al composite during isothermal annealing was investigated. The results showed that the residual stresses relaxed in the whole deformation layer especially when the annealing temperature was higher than 200 °C. The relaxation process during isothermal annealing could be described precisely using Zener-Wert-Avrami function. Because of high intensity dislocation around reinforcements producing a large amount of stored energy, the residual stress relaxation activation enthalpy of shot peened SiCw/Al was smaller than self-diffusion activation enthalpy of pure aluminum. According to the analysis of full-width at half-maximum (FWHM) of the shot peened composite in different annealing temperatures, it can be concluded the recovery and recrystallization behavior became intensely when anneal temperature was larger than 200 °C. The small relaxation of residual stress in low annealing temperature was mainly due to partly recovery and recrystallization in a very low level. Content Type Journal Article Pages 1-5 DOI 10.1007/s11665-011-9982-4 Authors Junjie Huang, School of Material Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240 People’s Republic of China Zhou Wang, School of Material Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240 People’s Republic of China Kai Bian, School of Material Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240 People’s Republic of China Chuanhai Jiang, School of Material Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240 People’s Republic of China Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    The precipitation of secondary carbides in the laser melted high chromium cast steels during tempering at 300-650 °C for 2 h in air furnace was characterized and the present phases was identified, by using transmission electron microscopy. Laser melted high chromium cast steel consists of austenitic dendrites and interdendritic M 23 C 6 carbides. The austenite has such a strong tempering stability that it remains unchanged at temperature below 400 °C and the secondary hardening phenomenon starts from 450 °C to the maximum value of 672 HV at 560 °C. After tempering at 450 °C fine M 23 C 6 carbides precipitate from the supersaturated austenite preferentially. In addition, the dislocation lines and slip bands still exist inside the austenite. While tempering at temperature below 560 °C, the secondary hardening simultaneously results from the martensite phase transformation and the precipitation of carbides as well as dislocation strengthening within a refined microstructure. Moreover, the formation of the ferrite matrix and large quality of coarse lamellar M 3 C carbides when the samples were tempered at 650 °C contributes to the decrease of hardness. Content Type Journal Article Pages 1-8 DOI 10.1007/s11665-011-9983-3 Authors M. Y. Li, College of Electromechanical Engineering, China University of Petroleum, Dongying, 257061 China Y. Wang, College of Electromechanical Engineering, China University of Petroleum, Dongying, 257061 China B. Han, College of Electromechanical Engineering, China University of Petroleum, Dongying, 257061 China Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    Post-weld annealing treatment (PWAT) process was developed to improve the plasticity of friction-stir-welded 2024 aluminum alloy. The effect of the PWAT on plastic deformation behavior and microstructure of the joints were studied using tensile test, the ASAME ® automatic strain measuring system, and the electron backscattered diffraction (EBSD). It is found that the elongation of the as-welded joint can be improved by PWAT and increases with the decreasing PWAT temperature. The maximum elongation of the PWAT joints can reach up to 160% of that of the as-welded joint, and the joints exhibit no decrease in the tensile strength. The deformation inhomogeneity of the as-welded joint is significantly improved by large plastic strain occurring in the thermo-mechanically affected zone (TMAZ) when the PWAT temperature is lower than 250°. As the PWAT temperature increases, the deformation in the weld nugget is found to be more beneficial than that in the TMAZ for improving the plasticity of the joint. The high plasticity of the joint is attributed to the presence of the fine-equiaxed grains in the weld nugget during PWAT. Content Type Journal Article Pages 1-7 DOI 10.1007/s11665-011-9981-5 Authors S. J. Yuan, National Key Laboratory of Advanced Welding Production Technology, Harbin Institute of Technology, Harbin, 150001 People’s Republic of China Z. L. Hu, National Key Laboratory of Advanced Welding Production Technology, Harbin Institute of Technology, Harbin, 150001 People’s Republic of China X. S. Wang, National Key Laboratory of Advanced Welding Production Technology, Harbin Institute of Technology, Harbin, 150001 People’s Republic of China G. Liu, National Key Laboratory of Advanced Welding Production Technology, Harbin Institute of Technology, Harbin, 150001 People’s Republic of China H. J. Liu, National Key Laboratory of Advanced Welding Production Technology, Harbin Institute of Technology, Harbin, 150001 People’s Republic of China Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    AA1100 aluminum alloy has gathered wide acceptance in the fabrication of light weight structures. Friction stir welding process (FSW) is an emerging solid state joining process in which the material that is being welded does not melt and recast. The process and tool parameters of FSW play a major role in deciding the joint characteristics. In this research, the relationships between the FSW parameters (rotational speed, welding speed, axial force, shoulder diameter, pin diameter, and tool hardness) and the responses (tensile strength, hardness, and corrosion rate) were established. The optimal welding conditions to maximize the tensile strength and minimize the corrosion rate were identified for AA1100 aluminum alloy and reported here. Content Type Journal Article Pages 1-14 DOI 10.1007/s11665-011-9979-z Authors S. Rajakumar, Department of Manufacturing Engineering, Center for Materials Joining & Research (CEMAJOR), Annamalai University, Annamalainagar, Chidambaram, 608002 Tamil Nadu, India V. Balasubramanian, Department of Manufacturing Engineering, Center for Materials Joining & Research (CEMAJOR), Annamalai University, Annamalainagar, Chidambaram, 608002 Tamil Nadu, India Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    Laser cutting with the sine waveform is seldom reported. This article is a comparative study on Nd:YAG laser cutting using the continuous (CW), square, and sine waveforms. The materials used in this study were steel and stainless steel. It has been found that the cutting capability, in descending order, is: CW 〉 sine 〉 square. The cutting of steel (C ~0.3 wt.%) and AISI304 austenitic stainless steel may be satisfactorily described by the Steen model, irrespective of waveform. Steel is slightly easier to cut than stainless steel. Limitations of the present study are discussed and suggestions for future work are made. Content Type Journal Article Pages 1-8 DOI 10.1007/s11665-011-9987-z Authors K. H. Lo, Department of Electromechanical Engineering, Faculty of Science and Technology, The University of Macau, Macau, China Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description: Erratum to: Modeling and Analysis of Process Parameters for Evaluating Shrinkage Problems During Plastic Injection Molding of a DVD-ROM cover Content Type Journal Article Pages 1-1 DOI 10.1007/s11665-011-9960-x Authors H. Öktem, Gebze Vocational School, Department of Industrial Molding, University of Kocaeli, 41410 Çayırova, Kocaeli, Turkey Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    This article investigates the phase transitions of complex quaternary Al-Zn-Mg-Cu alloys with Zr addition at overaged conditions. Differential scanning calorimetry (DSC) is employed to quantitatively analyze the phase transformation phenomena of a wide range of 7xxx series alloys through endothermic and exothermic reactions. The DSC observations detailing heat effect peaks and thermal parameters of η′ dissolution contain valuable information on the presence of equilibrium phases and the optimum alloying element contents. Based on DSC experimental data and phase diagrams, the balance of critical properties such as strength and electrical conductivity of Al-Zn-Cu-Mg 7xxx series alloys has been studied by considering the formation, dissolution, and incipient melting of S and T phase, dissolution of η′ phase as well as the formation of η phase. Nine Al-Zn-Mg-Cu alloys have been studied through microstructural examination and detailed DSC analysis. The correlation between the properties and the DSC data of the selected alloys has been analyzed. Content Type Journal Article Pages 1-8 DOI 10.1007/s11665-011-9973-5 Authors X. M. Li, School of Materials Science and Engineering, Southeast University, Nanjing, 211189 People’s Republic of China M. J. Starink, Materials Research Group, School of Engineering Sciences, University of Southampton, Southampton, SO17 1BJ UK Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    When a metal matrix composite undergoes centrifugal casting, the velocity, deceleration, displacement, and segregation of its particles are modeled according to changes in the centrifugal radius, as well as by variations in the molten metal viscosity as the temperature decreases during the cooling process. A cast aluminum alloy A356 reinforced by 10 V% of silicon carbide particles (SiC), with a median diameter of 12 μm, was used to conduct the experiments, and a mathematical modeling showed that the particles’ volume fraction on the outer casting face varied according to whether the viscosity of the liquid metal used was constant or variable. If variations in viscosity during the cooling process are taken into account, then the volume fraction of the particles for a given time of centrifugation changes on the outer casting face, while it increases if the viscosity was constant. Modeling the particle segregation with variable viscosity produces results that are closer to those obtained with experiments than is the case when a constant viscosity is used. In fact, the higher the initial pouring and mold temperatures, the higher the effect of the viscosity variation on particle segregation. Content Type Journal Article Pages 1-13 DOI 10.1007/s11665-011-9873-8 Authors B. Balout, Department of Mechanical Engineering, École de Technologie Supérieure, 1100 Notre-Dame Street West, (Corner Peel), Montreal, QC H3C 1K3, Canada J. Litwin, Cégep de Saint-Laurent, 625 Avenue Sainte-Croix, Montreal, QC H4L 3X7, Canada Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    Vacuum diffusion bonding of stainless steel to copper was carried out at a temperature ranging from 830 to 950 °C under an axial pressure of 3 MPa for 60 min with three kinds of interlayer metals: tin-bronze (TB) foil, Au foil, and TB-Au composite interlayer. The results showed that the grain boundary wetting was formed within the steel adjacent to the interface due to the contact melting between TB and Au when TB-Au composite interlayer was used. The grain boundary wetting could occur at a relatively low temperature of 830 °C and becomes significant with the increase of temperature. The tensile strength of the joint with TB-Au was higher than that with TB or Au interlayer separately and could be 228 MPa at the joining temperature of 850 °C. Furthermore, the axial compression ratio of the specimen joined at 850 °C was approximately 1.2%. Therefore, a reliable and precise joining of stainless steel to copper could be realized by diffusion bonding with the TB-Au composite interlayer at a comparatively low temperature. Content Type Journal Article Pages 1-5 DOI 10.1007/s11665-011-9870-y Authors Jiang-tao Xiong, State Key Laboratory of Solidification Processing, School of Materials Science and Engineering, Northwestern Polytechnical University, Xi’an, 710072 People’s Republic of China Qing Xie, Shaanxi Key Laboratory of Friction Welding Technologies, Northwestern Polytechnical University, Xi’an, 710072 People’s Republic of China Jing-long Li, Shaanxi Key Laboratory of Friction Welding Technologies, Northwestern Polytechnical University, Xi’an, 710072 People’s Republic of China Fu-sheng Zhang, Shaanxi Key Laboratory of Friction Welding Technologies, Northwestern Polytechnical University, Xi’an, 710072 People’s Republic of China Wei-dong Huang, State Key Laboratory of Solidification Processing, School of Materials Science and Engineering, Northwestern Polytechnical University, Xi’an, 710072 People’s Republic of China Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    The hot deformation behavior and microstructure evolution of 7075 Al/20% SiC p composite have been studied using the processing map. Compression tests were carried out in the temperature range of 300-500 °C and at the strain rate range of 0.001-1.0 s −1 . The stable and unstable regions in the map were verified with the microstructural observations of the deformed compression specimens. The “stable” regions, i.e., dynamic recrystallization and “unstable” regions such as debonding of SiC particles, matrix crack, and adiabatic shear band formation were identified from the processing map and compared with the reported microstructural observations of the deformed compression specimens. The optimum hot working conditions for this composite were identified. Content Type Journal Article Pages 1-6 DOI 10.1007/s11665-011-9871-x Authors M. Rajamuthamilselvan, Department of Manufacturing Engineering, Annamalai University, Annamalai Nagar, TamilNadu 608002, India S. Ramanathan, Department of Manufacturing Engineering, Annamalai University, Annamalai Nagar, TamilNadu 608002, India Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    Our research reported here is concerned with the development of physical aspects of shape memory linear actuators and drivers made from CuAlNi single crystals. Our study is focused on reactive stress generation and reversible deformation in the clamped CuAlNi single crystals due to martensitic transformations during thermal cycling. The crystals can reproduce force generation in heating to 560 K for many times, and one time in heating to 700 K with the maximal stress 350 MPa. The theoretical model and calculations of linear actuators that use shape memory single crystals is discussed and we also demonstrate real model of an actuator based on these crystals. Content Type Journal Article Pages 1-3 DOI 10.1007/s11665-011-9915-2 Authors S. Pulnev, Ioffe Physical-Technical Institute, Russian Academy of Sciences, Polytechnicheskaya, 26, St. Petersburg, Russia V. Nikolaev, Ioffe Physical-Technical Institute, Russian Academy of Sciences, Polytechnicheskaya, 26, St. Petersburg, Russia A. Priadko, Saint-Petersburg State Polytechnic University, St. Petersburg, Russia A. Rogov, Saint-Petersburg State Polytechnic University, St. Petersburg, Russia I. Vahhi, Saint-Petersburg State Polytechnic University, St. Petersburg, Russia Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    Twin wire arc-sprayed (TWAS) coating of commercially available SHS 7170-cored wire was obtained on Ti6AL4V alloy, and to improve its properties, it was further surface treated with high-power diode laser (HPDL). The cavitation erosion (CE) resistance of TWAS-coated samples was evaluated as per ASTM G-32-2003 and it was compared with laser-treated and untreated Ti6Al4V alloys. The CE resistance of TWAS-coated SHS 7170 samples after HPDL treatment has improved significantly. The main reasons for its improvement are elimination of pores, increased fracture toughness, reduced hardness, and brittleness. The CE resistance of HPDL-treated TWAS coating is compared with water droplet erosion resistance. It is observed that there is a similarity in the both the phenomenon. Content Type Journal Article Pages 1-5 DOI 10.1007/s11665-011-9949-5 Authors B. S. Mann, Surface Coatings and Treatment Laboratory, BHEL, Corporate R&D Division, Vikasnagar, Hyderabad, 500093 India Vivek Arya, Surface Coatings and Treatment Laboratory, BHEL, Corporate R&D Division, Vikasnagar, Hyderabad, 500093 India B. K. Pant, Surface Coatings and Treatment Laboratory, BHEL, Corporate R&D Division, Vikasnagar, Hyderabad, 500093 India Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    Electroplating technique was applied to coat carbon fibers with nickel. Before plating, the initial fibers were pretreated to improve the wettability in bath. The electroplating parameters were optimized to obtain high-quality nickel-coated carbon fibers, and the effects on plating were studied. The coated carbon fibers were characterized by SEM, XRD, and XPS. The coatings are uniform, smooth, bright, and adherent to carbon fibers not only along length but also along the diameter of the filaments, and mainly composed of pure nickel. Metal-carbon-oxygen bonds are present at the interface between nickel coatings and fibers, which provides the interfacial binding force. The results of performance tests showed that the nickel-coated fibers possess a good bonding strength not less than 78.5 kPa, and exhibit excellent oxidation resistance at high temperature. Compared with the initial fibers, the wettability with aluminum is also improved obviously. Content Type Journal Article Pages 1-7 DOI 10.1007/s11665-011-9958-4 Authors Zhongsheng Hua, School of Metallurgy and Resources, Anhui University of Technology, Maanshan, 243002 China Yihan Liu, School of Materials and Metallurgy, Northeastern University, 117 Box, Shenyang, 110004 China Guangchun Yao, School of Materials and Metallurgy, Northeastern University, 117 Box, Shenyang, 110004 China Lei Wang, School of Materials and Metallurgy, Northeastern University, 117 Box, Shenyang, 110004 China Jia Ma, School of Materials and Metallurgy, Northeastern University, 117 Box, Shenyang, 110004 China Lisi Liang, School of Materials and Metallurgy, Northeastern University, 117 Box, Shenyang, 110004 China Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    The propagation of uniaxial-stress planar shocks in granular materials is analyzed using a conventional shock-physics approach. Within this approach, both compression shocks and decompression waves are treated as (stress, specific volume, particle velocity, mass-based internal energy density, temperature, and mass-based entropy density) propagating discontinuities. In addition, the granular material is considered as being a continuum (i.e., no mesoscale features like grains, voids, and their agglomerates are considered). However, while the granular material is treated as a (smeared-out) continuum, it is recognized that it contains a solid constituent (parent matter), and that the structurodynamic properties (i.e., Equations of State (EOS) and Hugoniot relations) of the granular material are related to its parent matter. Three characteristic shock loading regimes of granular material are considered and, in each case, an analysis is carried out to elucidate shock attenuation and energy dissipation processes. In addition, an attempt is made to identify a metric (a combination of the material parameters) which quantifies the intrinsic ability of a granular material to attenuate a shock and dissipate the energy carried by the shock. Toward that end, the response of a typical granular material to a flat-topped compressive stress pulse is analyzed in each of the three shock loading regimes. Content Type Journal Article Pages 1-13 DOI 10.1007/s11665-011-9954-8 Authors Mica Grujicic, Department of Mechanical Engineering, Clemson University, 241 Engineering Innovation Building, Clemson, SC 29634-0921, USA B. Pandurangan, Department of Mechanical Engineering, Clemson University, 241 Engineering Innovation Building, Clemson, SC 29634-0921, USA W. C. Bell, Department of Mechanical Engineering, Clemson University, 241 Engineering Innovation Building, Clemson, SC 29634-0921, USA S. Bagheri, Department of Mechanical Engineering, Clemson University, 241 Engineering Innovation Building, Clemson, SC 29634-0921, USA Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    The effects of impurities on the resistivity distribution and polarity of multicrystalline silicon ingot prepared by directional solidification were investigated in this article. The shape of the equivalence line of the resistivity in the vertical and cross sections was determined by the solid-liquid interface. Along the solidification height of silicon ingot, the conductive type changed from p-type in the lower part of the silicon ingot to n-type in the upper part of the silicon ingot. The resistivity in the vertical section of the silicon ingot initially increased along the height of the solidified part, and reached its maximum at the polarity transition position, then decreased rapidly along the height of solidified part and approached zero on the top of the ingot because of the accumulation of impurities. The variation of resistivity in the vertical section of the ingot has been proven to be deeply relevant to the distribution of Al, B, and P in the growth direction of solidification. Content Type Journal Article Pages 1-5 DOI 10.1007/s11665-011-9952-x Authors S. H. Sun, School of Materials Science and Engineering, Dalian University of Technology, Linggong Road 2, Dalian, 116024 China Y. Tan, School of Materials Science and Engineering, Dalian University of Technology, Linggong Road 2, Dalian, 116024 China W. Dong, School of Materials Science and Engineering, Dalian University of Technology, Linggong Road 2, Dalian, 116024 China H. X. Zhang, School of Materials Science and Engineering, Dalian University of Technology, Linggong Road 2, Dalian, 116024 China J. S. Zhang, School of Materials Science and Engineering, Dalian University of Technology, Linggong Road 2, Dalian, 116024 China Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    The microstructural features of nanocarbide particles formed in Fe-Cr-W-V alloy were studied. A Fe-Cr-W-V alloy was first heat treated under different conditions. In this study, optical microscopy, scanning and transmission electron microscopy, x-ray diffraction, and hardness tester were used. The shape, size distribution, type, and lattice parameters of the extracted particles were investigated. The identified carbides were MC, M 7 C 3 , and M 23 C 6 . The particle size measurements showed that the mean length of carbide particles during 0.5, 5, and 20 h was about 103, 128, and 142 nm, respectively. Also, the mean thickness of carbide particles during 0.5, 5, and 20 h was about 54, 67, and 74 nm, respectively. Content Type Journal Article Pages 1-7 DOI 10.1007/s11665-011-0016-z Authors Abdul Javad Novinrooz, Materials Research School, NSTRI, Karaj, Iran Samira Moniri, Department of Physics, Karaj Branch, Islamic Azad University, Karaj, Iran Mohsen Asadi Asadabad, Materials Research School, NSTRI, Karaj, Iran Alireza Hojabri, Department of Physics, Karaj Branch, Islamic Azad University, Karaj, Iran Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    Acoustic emission (AE) technique is an efficient non-destructive method for detection and identification of various damage mechanisms in composite materials. Discrimination of AE signals related to different damage modes is of great importance in the use of this technique. For this purpose, integration of k -means algorithm and genetic algorithm (GA) was used in this study to cluster AE events of glass/epoxy composite during three-point bending test. Performing clustering analysis, three clusters with separate frequency ranges were obtained, each one representing a distinct damage mechanism. Furthermore, time-frequency analysis of AE signals was performed based on wavelet packet transform (WPT). In order to find the dominant components associated with different damage mechanisms, the energy distribution criterion was used. The frequency ranges of the dominant components were then compared with k -means genetic algorithm (KGA) outputs. Finally, SEM observation was utilized to validate the results. The obtained results indicate good performance of the proposed methods in the damage characterization of composite materials. Content Type Journal Article Pages 1-11 DOI 10.1007/s11665-011-0013-2 Authors Farzad Pashmforoush, Non-Destructive Testing Lab, Department of Mechanical Engineering, Amirkabir University of Technology, 424 Hafez Avenue, 15914 Tehran, Iran Mohamad Fotouhi, Non-Destructive Testing Lab, Department of Mechanical Engineering, Amirkabir University of Technology, 424 Hafez Avenue, 15914 Tehran, Iran Mehdi Ahmadi, Non-Destructive Testing Lab, Department of Mechanical Engineering, Amirkabir University of Technology, 424 Hafez Avenue, 15914 Tehran, Iran Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    The effect of austenitizing on the microstructure and hardness of two martensitic stainless steels was examined with the aim of supplying heat-treatment guidelines to the user that will ensure a martensitic structure with minimal retained austenite, evenly dispersed carbides and a hardness of between 610 and 740 HV (Vickers hardness) after quenching and tempering. The steels examined during the course of this examination conform in composition to medium-carbon AISI 420 martensitic stainless steel, except for the addition of 0.13% vanadium and 0.62% molybdenum to one of the alloys. Steel samples were austenitized at temperatures between 1000 and 1200 °C, followed by oil quenching. The as-quenched microstructures were found to range from almost fully martensitic structures to martensite with up to 35% retained austenite after quenching, with varying amounts of carbides. Optical and scanning electron microscopy was used to characterize the microstructures, and X-ray diffraction was employed to identify the carbide present in the as-quenched structures and to quantify the retained austenite contents. Hardness tests were performed to determine the effect of heat treatment on mechanical properties. As-quenched hardness values ranged from 700 to 270 HV, depending on the amount of retained austenite. Thermodynamic predictions (using the CALPHAD™ model) were employed to explain these microstructures based on the solubility of the carbide particles at various austenitizing temperatures. Content Type Journal Article Pages 1-10 DOI 10.1007/s11665-011-0043-9 Authors L. D. Barlow, Department of Materials Science and Metallurgical Engineering, University of Pretoria, Pretoria, South Africa M. Du Toit, Department of Materials Science and Metallurgical Engineering, University of Pretoria, Pretoria, South Africa Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    The formability of AISI 202 austenitic stainless steel was compared with that of type AISI 304 stainless steel. Type 202 is a low-nickel austenitic stainless steel alloyed with manganese and nitrogen. In this study, the formability of the two grades was examined using Erichsen cupping tests and room temperature uniaxial tensile tests performed at various angles to the rolling direction. AISI 202 appears to work-harden at a slightly higher rate than AISI 304, even though the austenite in type 202 is more stable than that in 304 with respect to the formation of deformation-induced α′ martensite. Although both grades are predicted to be susceptible to earing during deep drawing, AISI 202 displays a higher work-hardening exponent, higher average normal anisotropy, and a higher limiting drawing ratio than AISI 304. Similar cup heights were measured during Erichsen cupping tests, confirming that the two grades have very similar deep drawing properties. The results of this investigation therefore suggest that AISI 202 is a suitable alternative for AISI 304 in applications requiring good deep drawing properties. Content Type Journal Article Pages 1-5 DOI 10.1007/s11665-011-0044-8 Authors M. du Toit, Department of Materials Science and Metallurgical Engineering, University of Pretoria, Pretoria, 0002 South Africa H. G. Steyn, Department of Materials Science and Metallurgical Engineering, University of Pretoria, Pretoria, 0002 South Africa Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    Boronizing of AISI 1045 and ASTM W1-111/2 steels was carried out by pack boriding using Nd 2 O 3 -containing agent in the temperature range of 1053 to 1213 K. The effect of RE element Nd on boronizing kinetics was analyzed in terms of possible chemical reactions in boriding agent, surface elemental distribution and morphology evolution of the steels boronized at different temperatures. The results showed that the RE element Nd has two opposite effects on boronizing process, i.e., promoting effect at high temperatures and hindering effect at low temperatures. Boronizing using Nd 2 O 3 -containing agent can remarkably reduce the diffusion activation energy at higher temperatures. Empirical equations relating the boride layer thickness with processing time and temperature are established. Based on these equations, the contour diagrams of boride layer thickness for the studied steels boronized with addition of 5% Nd 2 O 3 are presented. Content Type Journal Article Pages 1-9 DOI 10.1007/s11665-011-0053-7 Authors Z. G. Su, Key Laboratory of Automobile Materials, Ministry of Education, Department of Materials Science and Engineering, Nanling Campus of Jilin University, Changchun, 130025 China X. X. Lv, Key Laboratory of Automobile Materials, Ministry of Education, Department of Materials Science and Engineering, Nanling Campus of Jilin University, Changchun, 130025 China J. An, Key Laboratory of Automobile Materials, Ministry of Education, Department of Materials Science and Engineering, Nanling Campus of Jilin University, Changchun, 130025 China Y. L. Yang, Songyuan Daduo Oilfield Accessory Industry Co. Ltd., Songyuan, 138000 China S. J. Sun, Songyuan Daduo Oilfield Accessory Industry Co. Ltd., Songyuan, 138000 China Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    Luminescent composites of poly(methylmethacrylate) (PMMA) and nanophosphors (Zn 2 SiO 4 :Mn 2+ , Zn 2 SiO 4 :Eu 3+ ) were prepared by dispersion casting method. It was found that nanoparticles embedded in PMMA matrix preserve their typical phosphorescence emission. The influence of Zn 2 SiO 4 nanofillers on thermal properties of PMMA was also investigated. A shift towards higher glass transition temperatures and slight improvements in thermal stability of the nanocomposites compared to pure PMMA were observed and are discussed herein. Content Type Journal Article Pages 1-5 DOI 10.1007/s11665-011-0049-3 Authors Ljubica Đačanin, Department of Physics, University of Novi Sad, 21000 Novi Sad, Serbia Svetlana R. Lukić, Department of Physics, University of Novi Sad, 21000 Novi Sad, Serbia Dragoslav M. Petrović, Department of Physics, University of Novi Sad, 21000 Novi Sad, Serbia Željka Antić, Vinča Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, 11001 Belgrade, Serbia Radenka Krsmanović, Vinča Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, 11001 Belgrade, Serbia Milena Marinović-Cincović, Vinča Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, 11001 Belgrade, Serbia Miroslav D. Dramićanin, Vinča Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, 11001 Belgrade, Serbia Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    Cavitation erosion is a frequently observed phenomenon in underwater engineering materials and is the primary reason for component failure. The damage due to cavitation erosion is not yet fully understood, as it is influenced by several parameters, such as hydrodynamics, component design, environment, and material chemistry. This article gives an overview of the current state of understanding of cavitation erosion of materials used in hydroturbines, coatings and coating methodologies for combating cavitation erosion, and methods to characterize cavitation erosion. No single material property fully characterizes the resistance to cavitation erosion. The combination of ultimate resilience, hardness, and toughness rather may be useful to estimate the cavitation erosion resistance of material. Improved hydrodynamic design and appropriate surface engineering practices reduce damage due to cavitation erosion. The coatings suggested for combating the cavitation erosion encompasses carbides (WC Cr 2 C 3 , Cr 3 C 2 , 20CrC-80WC), cermets of different compositions (e.g., 56W 2 C/Ni/Cr, 41WC/Ni/Cr/Co), intermetallic composites, intermetallic matrix composites with TiC reinforcement, composite nitrides such as TiAlN and elastomers. A few of them have also been used commercially. Thermal spraying, arc plasma spraying, and high velocity oxy-fuel (HVOF) processes have been used commercially to apply the coatings. Boronizing, laser surface hardening and cladding, chemical vapor deposition, physical vapor deposition, and plasma nitriding have been tried for surface treatments at laboratory levels and have shown promise to be used on actual components. Content Type Journal Article Pages 1-13 DOI 10.1007/s11665-011-0051-9 Authors Raghuvir Singh, Council of Scientific & Industrial Research-National Metallurgical Laboratory (CSIR-NML), Jamshedpur, 831007 India S. K. Tiwari, Council of Scientific & Industrial Research-National Metallurgical Laboratory (CSIR-NML), Jamshedpur, 831007 India Suman K. Mishra, Council of Scientific & Industrial Research-National Metallurgical Laboratory (CSIR-NML), Jamshedpur, 831007 India Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    Nondestructive eddy current technique has long been used to detect discontinuities in materials. However, recently, its application has been extended to characterize materials' microstructure and properties. In the present article, four mild carbon steel bars with different chemical compositions (AISI 1015, 1035, 1045, and 1080) were obtained in annealed condition. Besides, to determine the effect of microstructure, six ductile cast iron bars with the same chemical composition and different pearlite contents were prepared. The pearlite percentage and estimated hardness values were determined by eddy current nondestructive technique, and the results were compared with the data obtained from conventional metallographic and hardness testing methods. The results indicate that the eddy current is a sensitive comparative technique to detect the microstructure (directly) as well as the mechanical (indirectly) changes of mild carbon steel and ductile cast iron parts. Content Type Journal Article Pages 1-6 DOI 10.1007/s11665-011-0047-5 Authors Mehrdad Kashefi, Department of Materials Science and Metallurgical Engineering, Engineering Faculty, Ferdowsi University of Mashhad, Mashhad, Iran Saeed Kahrobaee, Department of Materials Science and Metallurgical Engineering, Engineering Faculty, Ferdowsi University of Mashhad, Mashhad, Iran Mohammad Hossien Nateq, Department of Materials Science and Metallurgical Engineering, Engineering Faculty, Ferdowsi University of Mashhad, Mashhad, Iran Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    Using scanning electron microscopy, transmission electron microscopy, and X-ray diffraction, some microscopic experiments and analyses were performed to explain the microscopic mechanism of strengthening under low-amplitude loads below the fatigue limit (SLAL). The experimental results show that the microscopic mechanism of SLAL could be dislocation-accumulation and grain boundary strengthening to low-strength material without strengthening by surface heat treatment. After SLAL, the microstructure imperfections can be improved and the fatigue resistance can be enhanced. Macroscopically, the fatigue strength and life of structures can be obviously improved and increased. Content Type Journal Article Pages 1-8 DOI 10.1007/s11665-011-0050-x Authors Songlin Zheng, Institute of Vehicle Engineering, College of Mechanical Engineering, University of Shanghai for Science and Technology, No. 516 Jungong Road, Shanghai, 200093 China Xi Lu, Institute of Vehicle Engineering, College of Mechanical Engineering, University of Shanghai for Science and Technology, No. 516 Jungong Road, Shanghai, 200093 China Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    This article reports a research study that shows the effect of shoulder diameter size on the resulting weld properties of dissimilar friction stir welds between 5754 aluminum alloy (AA) and C11000 copper (Cu). Welds were produced using three different shoulder diameter tools: 15, 18, and 25 mm by varying the rotational speed between 600 and 1200 rpm and the traverse speed between 50 and 300 mm/min to achieve the best result. Each parameter combination was chosen to represent different heat input conditions (low, intermediates and high). The welds were characterized through microstructural evaluation, tensile testing, microhardness measurements, x-ray diffraction analysis, and electrical resistivity. Microstructural evaluation of the welds revealed that the welds produced consisted of all the friction stir welding (FSW) microstructure zones with organized flow lines comprising mixture layers of aluminum (Al) and copper (Cu) at the Stir Zones. The average Ultimate Tensile Strength (UTS) of the welds considered ranged from 178 to 208 MPa. Higher Vickers microhardness values were measured at the joint interfaces of all the welds because of the presence of intermetallic compounds in these regions. The x-ray diffraction analysis revealed the presence of Al 4 Cu 9 and Al 2 Cu intermetallics at the interfacial regions, and low electrical resistivities were obtained at the joint interfaces. An optimized parameter setting for FSW of Al and Cu was obtained at the weld produced at 950 rpm and 50 mm/min with the 18-mm shoulder diameter tool. Content Type Journal Article Pages 1-6 DOI 10.1007/s11665-011-0046-6 Authors E. T. Akinlabi, Department of Mechanical Engineering Science, University of Johannesburg, P.O. Box 524, Auckland Park Kingsway Campus, Auckland Park, Johannesburg, 2006 South Africa Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    In this article, the bainitic transformation during austempering was studied for a 2.11% Al containing ductile iron under different isothermal holding times. The austenitizing time and temperature were selected to be 60 min and 920 °C, respectively, referring to previous studies. The isothermal austempering heat treatments were performed at 350 °C for different durations. Microstructures have been examined by optical microscopy, scanning electron microscopy, and transmission electron microscopy. Microstructural investigations revealed that austempering treatment at 350 °C for durations up to 100 min results in microstructures consisting of carbide-free bainitic ferrite with considerable amounts of retained austenite while the extension of isothermal transformation time leads to precipitation of carbides. Hardness measurements were also carried out the results of which were shown to be consistent with microstructural evolutions. Content Type Journal Article Pages 1-8 DOI 10.1007/s11665-011-0086-y Authors H. R. Erfanian-Naziftoosi, Department of Materials Engineering, Faculty of Engineering, Ferdowsi University of Mashhad, P.O. Box 91775-1111, Mashhad, Iran N. Haghdadi, Department of Materials Engineering, Faculty of Engineering, Ferdowsi University of Mashhad, P.O. Box 91775-1111, Mashhad, Iran A. R. Kiani-Rashid, Department of Materials Engineering, Faculty of Engineering, Ferdowsi University of Mashhad, P.O. Box 91775-1111, Mashhad, Iran Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    In this study, the effects of stress-assisted heat treatment on the microstructure and phase transformation of a Ti-rich (Ti-49.52 at.% Ni) shape memory alloy were investigated. For this purpose, the alloy was heat treated at temperature of 500 °C for 10 h under applied stresses of 100 and 200 MPa. XRD, TEM, and repeated thermal cycling were employed to study the microstructure and transformation behavior of the heat-treated materials. Room temperature XRD diffractogram of the stress-free heat-treated material showed a weak reflection of austenite (B2), while that for the stress-assisted heat-treated materials had a high intensity implying the presence of residual austenite in the microstructure. TEM observations confirmed the presence of residual austenite and revealed mechanical twins as another constituent of the microstructure in the stress-assisted heat-treated materials. Moreover, with increasing the value of applied stress the size of mechanical twins was increased and a high density of structural defects was observed at the interfaces of the twins. DSC results demonstrated two-stage transformation in the initial cycles of transformation in the stress-assisted heat-treated material. After about eight cycles of transformation, the two-stage transformation has vanished, and a single-stage transformation remained up to 100 cycles. It was suggested that the accommodation of stresses at Ti 2 Ni/matrix interface provides a suitable condition for local transformation of B2 to B19′ that is manifested by a two-stage phase transformation. Introduction of structural defects during repeated thermal cycling may counteract the stress field at Ti 2 Ni/matrix interface leading to a single-stage transformation. Content Type Journal Article Pages 1-7 DOI 10.1007/s11665-011-0082-2 Authors A. Ahadi, Department of Materials Science and Engineering, Sharif University of Technology, Azadi Avenue, Tehran, Iran E. Rezaei, Department of Materials Science and Engineering, Sharif University of Technology, Azadi Avenue, Tehran, Iran Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    Apart from the necessity of surface modification based on different applications, in most of the cases, diffusion of carbon or foreign particles on the workpiece surface during micro-electrodischarge machining (micro-EDM) is avoidable, especially in finishing micro-EDM. This study aims to investigate different sources of materials that migrate to the machined surface during fine-finishing of micro-EDM of cemented tungsten carbide (WC-Co). The machined surfaces have been examined under scanning electron microscope and energy dispersive x-ray to investigate the changes in chemical composition. It has been observed that during finishing of micro-EDM, the major source of materials' transfer to both the workpiece and electrode is the diffusion of carbon that comes from the decomposition of the hydrocarbon dielectric. In addition, materials from both workpiece and electrode transfer to each other based on machining conditions and discharge energy. The migration occurs more frequently at lower gap voltages during die-sinking with micro-EDM because of low spark gap and stationary tool electrode. Milling micro-EDM results in lower amount of carbon migration and fewer surface defects that improve the overall surface finish significantly. Content Type Journal Article Pages 1-14 DOI 10.1007/s11665-011-0083-1 Authors M. P. Jahan, Department of Mechanical Engineering, University of Arkansas, Fayetteville, AR, USA M. Rahman, Department of Mechanical Engineering, National University of Singapore, Singapore, 119260 Singapore Y. S. Wong, Department of Mechanical Engineering, National University of Singapore, Singapore, 119260 Singapore Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    A program was conducted to research how to characterize the size and shape of micro-particles. These can act as graphite nuclei, but are altered by adding a commercial iron powder, or after a similar treatment combined with inoculation. Resin sand mold (RSM) and metal mold (MM) solidified sample structures were subjected to automatic image analysis. In general, a higher cooling rate, typical for MM solidification, favors smaller size and more compact particles, even in RSM media. Iron powder treatment led to the largest particles with unusual morphologies, better defined by complex shape factors, which employ actual perimeters, rather than the simpler median size and aspect ratio method. Conventional inoculation employed after an iron powder treatment altered the particles (smaller and more compact), which benefited their effectiveness to act as graphite nuclei, especially at slower solidification rates in RSMs. The results confirm that promoting more compact micro-inclusions, at smaller sizes, involved in graphite nucleation, reduces the sensitivity to chill and improves the eutectic cell characteristics in gray cast iron. Content Type Journal Article Pages 1-7 DOI 10.1007/s11665-011-0081-3 Authors Stelian Stan, POLITEHNICA University of Bucharest, 313 Spl. Independentei, 060042 Bucharest, Romania Mihai Chisamera, POLITEHNICA University of Bucharest, 313 Spl. Independentei, 060042 Bucharest, Romania Iulian Riposan, POLITEHNICA University of Bucharest, 313 Spl. Independentei, 060042 Bucharest, Romania Nicoleta Ivan, POLITEHNICA University of Bucharest, 313 Spl. Independentei, 060042 Bucharest, Romania Michael Barstow, Consultant Metallurgist, Fremont, CA, USA Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    There is a lack of comprehensive understanding concerning failure characteristics of three-steel sheet resistance spot welds. In this article, macro/microstructural characteristics and failure behavior of 1.25/1.25/1.25 mm three-sheet low carbon steel resistance spot welds are investigated. To evaluate the mechanical properties of the joint, the tensile-shear test was performed in three different joint designs. Mechanical performance of the joint was described in terms of peak load, energy absorption, and failure mode. The critical weld nugget size required to insure pullout failure mode was obtained for each joint design. It was found that the joint design significantly affects the mechanical properties and the tendency to fail in the interfacial failure mode. It was also observed that stiffer joint types exhibit higher critical weld size. Fusion zone size along sheet/sheet interface proved to be the most important controlling factor of spot weld peak load and energy absorption. Content Type Journal Article Pages 1-7 DOI 10.1007/s11665-011-0078-y Authors M. Pouranvari, Young Researchers Club, Dezful Branch, Islamic Azad University, Dezful, Iran S. P. H. Marashi, Mining and Metallurgical Engineering Department, Amirkabir University of Technology, Tehran, Iran Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    An overview is presented of general aspects of a methodology for inverse thermal analysis of drop-by-drop liquid-metal deposition based on Green’s functions. This methodology is constructed according to the general physical characteristics of rapid prototyping processes employing drop-by-drop liquid-metal deposition. This methodology represents a specific extension of a methodology using basis functions that was introduced previously for inverse analysis of welding processes, and of energy deposition in general. The formal structure of the methodology follows from a specific definition of the inverse heat transfer problem, which is well posed for inverse analysis of heat deposition processes. This definition is based on the assumption of the availability of information concerning spatially distributed boundary and constraint values. This information would be obtained in principle from both experimental measurements obtained in the laboratory, as well as numerical simulations performed using models having been constructed using basic theory. Content Type Journal Article Pages 1-13 DOI 10.1007/s11665-011-0075-1 Authors S. G. Lambrakos, Center for Computational Materials, Code 6390, Materials Science and Technology Division, Naval Research Laboratory, Washington, DC, USA A. Shabaev, Department of Physics, George Mason University, Fairfax, VA, USA N. Bernstein, Center for Computational Materials, Code 6390, Materials Science and Technology Division, Naval Research Laboratory, Washington, DC, USA K. P. Cooper, Center for Computational Materials, Code 6390, Materials Science and Technology Division, Naval Research Laboratory, Washington, DC, USA Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    Nano-hydroxyapatite (HAP) has been synthesized using sol-gel technique. Calcium nitrate tetrahydrate and potassium dihydrogen phosphate were used as precursors for calcium and phosphorus, respectively. A detailed study on its transformation during calcination at two crucial temperatures has been undertaken. The synthesized nanopowder was calcined at 600 and 800 °C for different time periods. The results revealed that the obtained powders after calcining at 600 and 800 °C are composed of hydroxyapatite nanoparticles. The nano-HAP powders were characterized by x-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy, thermal gravimetric analysis (TGA), and BET surface area analyzer techniques. The results indicate that crystallite size as well as crystallinity of synthesized HAP nanopowders increase with increase in calcination temperature as well as calcination time, but the effect of temperature is more prominent as compared to that of calcination time. TEM micrograph revealed the presence of majority of HAP powder particles as agglomerates and a few as individual particles. It also revealed that HAP produced after sintering at 600 °C is 26-45 nm in size, which is well in agreement with the crystallite size calculated using XRD data. TGA study showed the thermal stability of the as-synthesized nano-HAP powder. The BET surface area decreased with increase in calcination temperature and time. The results clearly demonstrate the significant role of calcination parameters on the characteristics of nano-HAP powders. Content Type Journal Article Pages 1-7 DOI 10.1007/s11665-011-0059-1 Authors Kapoor Seema, University Institute of Chemical Engineering & Technology, Panjab University, Chandigarh, 160014 India Batra Uma, Department of Materials & Metallurgical Engineering, PEC University of Technology, Sector-12, Chandigarh, 160012 India Kohli Suchita, University Institute of Chemical Engineering & Technology, Panjab University, Chandigarh, 160014 India Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    The present investigation was carried out to study the effect of manganese and copper addition, singly as well as in combination, on the microstructure, micro-segregation, and mechanical properties of ductile irons. Alloy A (3.18C, 2.64Si, 0.45Mn), alloy B (3.35C, 2.51Si, 0.82Mn), alloy C (3.16C, 2.80Si, 1.08Mn, 0.56Cu), and alloy D (3.18C, 3.00Si, 1.04Mn, 1.13Cu) were melted and cast in the form of Y-block test pieces. The cast microstructures varied from ferrito-pearlitic in alloys A, B, and C to pearlitic in alloy D. However, on XRD analysis and SEM examination, the presence of martensite patches was also detected. There was a marginal decrease in nodule count in alloy B. In alloys C and D, nodule counts were higher, but the proportion of ferrite decreased drastically. Alloy D was found to be the strongest (UTS ≈ 800 MPa, El = 5%) with alloys A and C coming next in strength; while alloy B was weakest of the four. The presence of martensite patches in association with pearlite appears to be responsible for low toughness of these alloys. Microprobe analysis shows some silicon segregation near the graphite nodules and practically little segregation of manganese. Elemental mapping by FE-SEM does not indicate any manganese segregation. Content Type Journal Article Pages 1-9 DOI 10.1007/s11665-011-0058-2 Authors Ranjan Kumar Dasgupta, Materials Engineering Division, Central Mechanical Engineering Research Institute, Durgapur, India Dipak Kumar Mondal, Department of Metallurgical and Materials Engineering, National Institute of Technology, Durgapur, India Ajit Kumar Chakrabarti, Department of Metallurgical and Materials Engineering, National Institute of Technology, Durgapur, India Ashis Chandra Ganguli, Department of Metallurgical and Materials Engineering, National Institute of Technology, Durgapur, India Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    A jacketed underground pipeline made of 304 stainless steel tubing to transport utility water in a petrochemical plant at ambient temperature was perforated after few months of operation. Perforation started preferentially at the outer bottom surface of the pipe in the weld heat-affected zones where the insulating coating was damaged. Detailed microstructural characterization was carried out to determine the cause of failure using optical metallography, x-ray diffraction, scanning electron microscopy combined with energy dispersive spectroscopy, and transmission electron microscopy. Experimental results indicated that the failure occurred by interaction between the outer bottom surface of the pipe and surrounding environment leading to pitting and stress corrosion cracking in the presence of chloride ions. This could have been aided by residual welding stresses and the characteristic low stacking fault energy of the material. Content Type Journal Article Pages 1-6 DOI 10.1007/s11665-011-0076-0 Authors H. M. Tawancy, Centre for Engineering Research and Centre of Research Excellence in Corrosion, Research Institute, King Fahd University of Petroleum & Minerals, P.O. Box 1639, Dhahran, 31261 Saudi Arabia Luai. M. Al-Hadhrami, Centre for Engineering Research and Centre of Research Excellence in Corrosion, Research Institute, King Fahd University of Petroleum & Minerals, P.O. Box 1639, Dhahran, 31261 Saudi Arabia Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    This work presents an experimental evaluation of yield strength, tensile strength, and impact toughness of 7075 Al alloy. The extended finite element method (XFEM) has been chosen for quasi-static crack growth simulations using Charpy impact energy as the crack growth criterion for both Bulk and ultrafine-grained (UFG) 7075 Al alloy. The 7075 Al alloy is rolled for different thickness reductions (40 and 70%) at cryogenic (liquid nitrogen) temperature, and its mechanical properties are studied by performing the tensile and Charpy impact testing. The microstructural characterization of the alloy was carried out using field emission scanning electron microscopy (FE-SEM). The rolling of the Al alloy at cryogenic temperature suppresses dynamic recovery, and dislocation cells formed during processing, transformed into fully formed ultrafine-grains (600 nm) at 70% thickness reduction. The impact energy used as the crack growth criterion under quasi-static loading condition based on the Griffith energy concept. The elastic-plastic ductile fracture simulations are performed by XFEM using ABAQUS Software (Version 6.9). For crack modeling, two different types of functions are used to model a crack based on partition of unity concept. A discontinuous function is used to model the portion behind the crack tip, whereas crack tip is modeled by near-tip asymptotic functions. This permits the crack is to be represented explicitly without meshing the crack surfaces, thus crack propagation simulations can be carried out without a need of re-meshing. Strain energy release and stress distribution ahead of the crack tip is found for some practical crack problems. The numerical examples indicate a significant improvement in crack growth properties of UFG 7075 Al alloy as compared to its bulk form due to an effective grain refinement. Content Type Journal Article Pages 1-15 DOI 10.1007/s11665-011-0062-6 Authors Prosenjit Das, Foundry Section, Central Mechanical Engineering Research Institute, Durgapur, 713209 India I. V. Singh, Department of Mechanical and Industrial Engineering, Indian Institute of Technology Roorkee, Roorkee, 247667 India R. Jayaganthan, Department of Metallurgical and Materials Engineering & Centre of Nanotechnology, Indian Institute of Technology Roorkee, Roorkee, 247667 India Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    In the present study, a suitable machine was developed in the laboratory to investigate the fatigue-wear behavior of the untreated 316L austenitic stainless steel and samples treated by plasma electrolytic nitrocarburizing process under different combinations of cyclic loading and contact pressure. The fracture cycles as a function of bending stress were recorded while a constant contact pressure was applied simultaneously. As a result, the PEN/C treated specimens exhibited a higher resistance (about 40% for 15.6 N contact load and about 60% for 25 N contact load) under the application of simultaneous cyclic stress and contact pressure. Also it was shown that under a range of combined fatigue and wear stresses, the specimens exhibit a better life than the conditions of performing wear or fatigue tests separately and this effect was much more observable for PEN/C-treated samples. The gravimetrical weight loss values in the fatigue-wear test were also measured at intervals 5000 to 300,000 cycles (with the contact stress = 6.25 MPa and the bending stress = 87 MPa). The results showed a better wear resistance for the treated surface at the first stage of the process. Content Type Journal Article Pages 1-6 DOI 10.1007/s11665-011-0072-4 Authors Fatemeh Mahzoon, Materials Science and Engineering Department, Shiraz University, Shiraz, Iran Seyed Ahmad Behgozin, Shiraz Bahonar Technical College, Shiraz, Iran Mohammad Ebrahim Bahrololoom, Materials Science and Engineering Department, Shiraz University, Shiraz, Iran Sirus Javadpour, Materials Science and Engineering Department, Shiraz University, Shiraz, Iran Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    In this article, friction stir welded T-joints of innovative dissimilar aluminum alloys have been produced and tested with the aim to investigate the feasibility of using this joining technique, in this configuration, in the aerospace field with the final aim to save weight. The introduction of both this new welding technique and innovative alloys, such as AA 2198 and AA 6056, could allow making lighter and stronger structures. Some experiments, carried out previously, have shown that the fixturing device, the tool geometry, and the tilt angle play a significant role in the joint soundness. A wide experimental characterization has been carried out on FSW T-joints of AA 6056 T4 extrudes to AA 2198 T3 rolled plates. The results attained allow to put in evidence some critical issues on the investigated configuration and can be considered as a further acquired knowledge in the understanding and the design of friction stir processes. Content Type Journal Article Pages 1-9 DOI 10.1007/s11665-011-0073-3 Authors A. Astarita, Department of Materials and Production Engineering, University of Naples Federico II, Naples, Italy A. Squillace, Department of Materials and Production Engineering, University of Naples Federico II, Naples, Italy A. Scala, Department of Materials and Production Engineering, University of Naples Federico II, Naples, Italy A. Prisco, Operations—Manufacturing Research & Development, ALENIA Aeronautica S.p.A, Turin, Italy Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    Andalusite as a refractory material can be transformed to mullite and a silica-rich liquid phase in a temperature range of 1100-1600 °C. In this paper, the influences of MgO and CaO mineralizers on transformation of andalusite to mullite were investigated. Different amounts of MgO and CaO were introduced to andalusite by solution (precipitation) method. Then the precipitated particles were pressed, dried, and fired at 1300, 1400, 1500, and 1600 °C for 2 h. The microstructures of these samples were studied by XRD and SEM. The results showed that the addition of MgO and CaO affected mullitization of andalusite, so that the addition of these oxides increased the amount of mullite formation in andalusite. Content Type Journal Article Pages 1-8 DOI 10.1007/s11665-011-0071-5 Authors H. Pooladvand, Science and Research Branch, Islamic Azad University, Tehran, Iran S. Baghshahi, Imam Khomeini International University, Qazvin, Iran B. Mirhadi, School of Metallurgy and Materials Engineering, Iran University of Science and Technology (IUST), Tehran, Iran A. R. Souri, University of Malayer, Malayer, Iran H. Arabi, Center of Excellence for Advanced Materials and Processing, School of Metallurgy and Materials Engineering, Iran University of Science and Technology (IUST), Tehran, Iran Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    The mechanical properties of ultrafine lath-shaped low-carbon steel plates were studied. Results indicated that the hardness and tensile strength of the conventional low-carbon steel are HRC 19 and 410 MPa, respectively. With the decreased grain size of the ultrafine lath-shaped steel plates, the hardness and tensile strength of the test samples rapidly increase. Mechanical properties are at their optimum when grain size reaches 90 nm. Furthermore, both the hardness and the tensile strength values reach their maximum, which are HRC 53.5 and 1217 MPa, respectively. Content Type Journal Article Pages 1-4 DOI 10.1007/s11665-011-0055-5 Authors Xin Li, College of Materials Science and Engineering, Yanshan University, Qinhuangdao, 066004 China Tianfu Jing, College of Materials Science and Engineering, Yanshan University, Qinhuangdao, 066004 China Manman Lu, College of Materials Science and Engineering, Yanshan University, Qinhuangdao, 066004 China Jingwu Zhang, College of Materials Science and Engineering, Yanshan University, Qinhuangdao, 066004 China Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    In this research, the constitutive relationships of BT25 titanium alloy based on regression and artificial neural network (ANN) methods were established and studied by analyzing the results of hot compression tests. The isothermal compression tests were conducted on a Gleeble 1500 thermo-mechanical simulator in the deformation temperatures ranging from 940 to 1000 °C with an interval of 20 °C and the strain rates of 0.01, 0.1, 1.0, and 10.0 s −1 with a height reduction of 60%. The average deformation activation energy of the alloy was derived as 623.26 kJ/mol at strain of 0.7 by using the non-linear regression method and assuming a hyperbolic sine equation between the stress, strain rate, and deformation temperature. On the basis of the experimental data samples, an ANN model was proposed and trained. The hot processing parameters of temperature, strain rate, and strain were used as the input variables and the flow stress as the output variable. The comparison of experimental flow stresses with predicted values by ANN model and calculated value by regression method was carried out. It was found that the predicted results by ANN are in a good agreement with the experimental values, which indicates that the predicted accuracy of the constitutive relationship established by ANN model is higher than that using the multivariable regression method. Content Type Journal Article Pages 1-7 DOI 10.1007/s11665-011-0061-7 Authors Xiong Ma, State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an, 710072 China Weidong Zeng, State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an, 710072 China Fei Tian, State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an, 710072 China Yu Sun, State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an, 710072 China Yigang Zhou, State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an, 710072 China Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    Effects of plasma nitriding on the tensile behavior of Al-Mg-Si alloy were investigated in this study. The specimens were nitrided at 70 W input pulsed DC power at 1 mbar pressure of nitrogen for 4 h using glow discharge plasma. The formation of aluminum nitride layer on the specimen's surface was confirmed by the XRD analysis. Stress-strain curves of both un-nitrided and nitrided specimens were obtained using Universal Testing Machine. The comparison of these curves reveals that yield stress, ultimate tensile stress, percentage elongation, and stress relaxation rate decrease after plasma nitriding. The changes in the tensile properties after nitriding have been correlated with the changes in the microstructure of the specimens as observed using scanning electron microscope. Content Type Journal Article Pages 1-4 DOI 10.1007/s11665-011-0054-6 Authors I. M. Ghauri, Centre for Advanced Studies in Physics, GC University, Lahore, Pakistan R. Ahmad, Centre for Advanced Studies in Physics, GC University, Lahore, Pakistan F. E. Mubarik, Centre for Advanced Studies in Physics, GC University, Lahore, Pakistan Naveed Afzal, Centre for Advanced Studies in Physics, GC University, Lahore, Pakistan Sajjad Ahmed, Centre for Advanced Studies in Physics, GC University, Lahore, Pakistan R. Ayub, Centre for Advanced Studies in Physics, GC University, Lahore, Pakistan Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    Friction stir welding (FSW), a promising solid state joining process invented at TWI in 1991, was used to join 9 mm thick 7475 aluminum alloy which is considered essentially unweldable by fusion processes. In the present work, the process parameters such as tool rotational speed were varied from 300 to 1000 rpm for a travel speed of 50 mm/min and the influence of process parameters in terms of energy input on microstructure, hardness, tensile strength, and the corrosion property of 7475 aluminum joints was evaluated and analyzed. The maximum tensile strength of FSW joints was obtained at rotational speed of 400 rpm and traverse speed of 50 mm/min (59.2 kJ) which attributed maximum stirred zone area and maximum hardness. The maximum corrosion resistance properties of weld in 3.5% NaCl solution, however, were obtained at rotational speed of 1000 rpm and traverse speed of 50 mm/min. Furthermore, for a given weld, stirred zone showed improved corrosion properties than TMAZ. Content Type Journal Article Pages 1-10 DOI 10.1007/s11665-011-0074-2 Authors Rajesh Kumar Gupta, Welding Technology Centre, Metallurgical and Material Engineering Department, Jadavpur University, Kolkata, 700032 India Hrishikesh Das, Welding Technology Centre, Metallurgical and Material Engineering Department, Jadavpur University, Kolkata, 700032 India Tapan Kumar Pal, Welding Technology Centre, Metallurgical and Material Engineering Department, Jadavpur University, Kolkata, 700032 India Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    Microstructural modification and grain refinement due to addition of scandium in Al-6Si-0.3Mg alloy has been studied in this article. It is seen from the microstructure that the dendrites of the cast Al-6Si-0.3Mg alloy have been refined significantly because of addition of scandium. Increasing amount of scandium leads to a greater dendrite refinement. The age hardening effect has been studied by subjecting the alloys containing varying amounts of scandium ranging from 0.2 to 0.6 wt.% to isochronal and isothermal aging at various temperatures for different times. It is observed that addition of scandium is the most effective in suppressing the softening effect during prolonged aging treatment. Content Type Journal Article Pages 1-5 DOI 10.1007/s11665-011-0057-3 Authors M. S. Kaiser, Directorate of Advisory, Extension and Research Services, Bangladesh University of Engineering and Technology, Dhaka, 1000 Bangladesh M. R. Basher, Department of Materials and Metallurgical Engineering, Bangladesh University of Engineering and Technology, Dhaka, 1000 Bangladesh A. S. W. Kurny, Department of Materials and Metallurgical Engineering, Bangladesh University of Engineering and Technology, Dhaka, 1000 Bangladesh Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    The purpose of this study was to obtain a comprehensive understanding of the effects of cutting parameters (depth of cut, feed rate, and cutting speed) on the surface integrity of, in terms of superficial hardening, annealed brass during a turning process. The results indicate that no significant phase transformations occurred for any of the turning conditions evaluated; however, microstructural changes were observed, as well as changes in the superficial hardness were measured. It was found that when the studied cutting parameters increase, the superficial hardness increases, with the cutting speed having less influence (2.56%), and feed rate having the greatest effect (22.67%). Finally, a mathematical expression is proposed, which relates the cutting parameters to the maximum hardness obtained for a given cutting condition. Content Type Journal Article Pages 1-5 DOI 10.1007/s11665-011-0052-8 Authors O. Zurita, Department of Mechanics, Simon Bolivar University, Caracas, Venezuela V. Di Graci, Department of Mechanics, Simon Bolivar University, Caracas, Venezuela Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    T91 (9Cr1MoVNb), the martensitic heat-resistant steel, is widely applied in industries like power generation, petrochemical, nuclear, etc., and a wealth of researches has been conducted on its properties so far. However, actually for China, T91 was begun to be domestically manufactured only from the end of last century. Hence, thorough assessments of the China-made T91 steels are always urgently required, especially for its welded joints. In this paper, the relationship between mechanical properties and microstructures of the welded joints of one China-made T91 steel was experimentally discussed. Moreover, aging test and creep rupture test were utilized for both analyzing the heat strength and predicting the service life of the joints. Results showed that welded joints of this China-made T91 steel could exhibit sufficient strength under the operating conditions of most nuclear reactors used nowadays. Content Type Journal Article Pages 1-7 DOI 10.1007/s11665-011-0048-4 Authors Yi Gong, Department of Materials Science, Fudan University, Shanghai, 200433 People’s Republic of China Zhen-Guo Yang, Department of Materials Science, Fudan University, Shanghai, 200433 People’s Republic of China Fa-Yun Yang, Power Station, Baosteel Group Co. Ltd., Shanghai, 201900 People’s Republic of China Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    In this study, the effect of Cu content on the superplastic-like behavior of Al-Mg alloys in coarse grain size condition has been studied. Five hot-rolled Al-Mg alloys with different Cu concentrations (0.5, 1.0, 1.5, and 2.0 wt.%) and without Cu were prepared. Tensile test specimens were machined parallel to the rolling direction. High-temperature elongation to failure tests were performed under a constant cross-head speed condition at different strain rates and temperatures. Grain size refinement is observed as Cu addition increases. Maximum tensile elongation of 373% could be achieved in the Al-4.5%Mg-1.5%Cu alloy with an average grain size of 28 μm at 500 °C and 1 × 10 −2  s −1 . Grain size refinement after superplastic deformation was also observed. Content Type Journal Article Pages 1-4 DOI 10.1007/s11665-011-0056-4 Authors Marco A. García-Bernal, Department of Aeronautical Engineering, Instituto Politécnico Nacional, ESIME Unidad Ticomán, Av. Ticomán No. 600, Col. San José Ticomán, 07340 México, D.F., Mexico D. Hernandez-Silva, Department of Metallurgical Engineering, Instituto Politécnico Nacional, ESIQIE, Apdo. Postal 118-392, 07738 México, D.F., Mexico V. M. Sauce-Rangel, Department of Aeronautical Engineering, Instituto Politécnico Nacional, ESIME Unidad Ticomán, Av. Ticomán No. 600, Col. San José Ticomán, 07340 México, D.F., Mexico Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    The design of the currently used Advanced Combat Helmet (ACH) has been optimized to attain maximum protection against ballistic impacts (fragments, shrapnel, etc.) and hard-surface collisions. However, the ability of the ACH to protect soldiers against blast loading appears not to be as effective. Polyurea, a micro-segregated elastomeric copolymer has shown superior shock-mitigation capabilities. In the present work, a combined Eulerian/Lagrangian transient non-linear dynamics computational fluid/solid interaction analysis is used to investigate potential shock-mitigation benefits which may result from different polyurea-based design augmentations of the ACH. Specific augmentations include replacement of the currently used suspension-pad material with polyurea and the introduction of a thin polyurea internal lining/external coating to the ACH shell. Effectiveness of different ACH designs was quantified by: (a) establishing the main forms of mild traumatic brain injury (mTBI); (b) identifying the key mechanical causes for these injuries; and (c) quantifying the extents of reductions in the magnitude of these mechanical causes. The results obtained show that while the ACH with a 2-mm-thick polyurea internal lining displays the best blast mitigation performance, it does not provide sufficient protection against mTBI. Content Type Journal Article Pages 1-18 DOI 10.1007/s11665-011-0065-3 Authors A. Grujicic, Department of Bioengineering, Clemson University, Clemson, SC 29634, USA M. LaBerge, Department of Bioengineering, Clemson University, Clemson, SC 29634, USA M. Grujicic, Department of Mechanical Engineering, Clemson University, 241 Engineering Innovation Building, Clemson, SC 29634-0921, USA B. Pandurangan, Department of Mechanical Engineering, Clemson University, 241 Engineering Innovation Building, Clemson, SC 29634-0921, USA J. Runt, Department of Material Science and Engineering, Pennsylvania State University, University Park, PA 16082, USA J. Tarter, Applied Research Laboratories, Pennsylvania State University, University Park, PA 16082, USA G. Dillon, Applied Research Laboratories, Pennsylvania State University, University Park, PA 16082, USA Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    In this article, the finite element and cellular automata models are coupled to determine static recrystallization kinetics after cold deformation of low carbon steels. The deformation analysis is first performed to predict the strain, stress, and stored energy distributions within the deformed steel employing the finite element software, ABAQUS. Then, the kinetics of static recrystallization and distribution of recrystallized grain size are evaluated by means of a cellular automata model together with the stored energy calculated by the deformation analysis. To examine the predictions, the experimental results of recrystallized fractions and grain sizes after cold side-pressing of low carbon steel are compared with the predicted ones, and a reasonable agreement is achieved. Content Type Journal Article Pages 1-9 DOI 10.1007/s11665-011-0063-5 Authors E. Afshari, Department of Materials Science and Engineering, Sharif University of Technology, Azadi Avenue, Tehran, Iran S. Serajzadeh, Department of Materials Science and Engineering, Sharif University of Technology, Azadi Avenue, Tehran, Iran Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    Mechanical properties and exfoliation corrosion behavior in Al-Cu-Mg alloy with various pre-strain percents were characterized in this study by means of hardness measurement, optical microscope, transmission electron microscope (TEM), x-ray diffraction (XRD), and electrochemical technique. The hardness of naturally aged alloy was significantly enhanced with increasing the pre-strain percents. The immersion tests and polarization measurements revealed that the pre-straining processing before natural aging reduced the resistance of the alloy to exfoliation corrosion (EXCO), which was mainly attributed to the increase of dislocations density and grain aspect ratio. The decrease of residual tensile stress may only play a minor role in the EXCO resistance. Content Type Journal Article Pages 1-6 DOI 10.1007/s11665-011-0040-z Authors Yao Li, Key Laboratory of Nonferrous Metal Materials Science and Engineering, Ministry of Education, Central South University, Changsha, 410083 China Zhiyi Liu, Key Laboratory of Nonferrous Metal Materials Science and Engineering, Ministry of Education, Central South University, Changsha, 410083 China Song Bai, Key Laboratory of Nonferrous Metal Materials Science and Engineering, Ministry of Education, Central South University, Changsha, 410083 China Lianghua Lin, Key Laboratory of Nonferrous Metal Materials Science and Engineering, Ministry of Education, Central South University, Changsha, 410083 China Lifang Gao, Key Laboratory of Nonferrous Metal Materials Science and Engineering, Ministry of Education, Central South University, Changsha, 410083 China Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    One of the most important issues that hinder the widespread use of friction stir (FS) processing, an effective microstructural modification technique, is the lack of accurate predictive tools that enable the selection of suitable processing parameters to obtain the desired grain structure. In this study, a model that is capable of predicting the resulting average grain size of a FS-processed material from process parameters is presented. The proposed model accounts for both dynamic recrystallization and grain growth. Several AZ31 magnesium samples were FS processed in different combinations of rotational and translational speeds. The thermal fields and resulting average grain size were measured, and the effective strain rates were approximated analytically. The results show that the proposed model is capable of predicting the resulting grain size of FS-processed materials. Content Type Journal Article Pages 1-6 DOI 10.1007/s11665-011-0039-5 Authors Basil M. Darras, Department of Mechanical Engineering, American University of Sharjah, Sharjah, UAE Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    Magnesium alloy AP65 was prepared by melting and casting. The corrosion behavior of the as-cast and solid solution (T4)-treated AP65 alloys in 3.5% sodium chloride solution was investigated by corrosion morphology observation, immersion test, and electrochemical measurements. The results show that the second phase Mg 17 Al 12 surrounded by a lead-enriched area distributes discontinuously along the grain boundaries in the as-cast AP65 alloy. The lead-enriched areas with high activity are susceptible to be attacked during immersion test and can act as places for preferential anodic dissolution. The corrosion resistance of the as-cast AP65 alloy can be improved after T4 treatment and the T4-treated alloy suffers general corrosion. Content Type Journal Article Pages 1-9 DOI 10.1007/s11665-011-0035-9 Authors Nai-guang Wang, School of Materials Science and Engineering, Central South University, Changsha, 410083 China Ri-chu Wang, School of Materials Science and Engineering, Central South University, Changsha, 410083 China Chao-qun Peng, School of Materials Science and Engineering, Central South University, Changsha, 410083 China Yan Feng, School of Materials Science and Engineering, Central South University, Changsha, 410083 China Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    Strain rate dependency of mechanical properties of tungsten carbide (WC)-filled bronze castings fabricated by centrifugal and sedimentation-casting techniques are examined, in this study. Both casting techniques are an attempt to produce a functionally graded material with high wear resistance at a chosen surface. Potential applications of such materials include shaft bushings, electrical contact surfaces, and brake rotors. Knowledge of strain rate-dependent mechanical properties is recommended for predicting component response due to dynamic loading or impact events. A brief overview of the casting techniques for the materials considered in this study is followed by an explanation of the test matrix and testing techniques. Hardness testing, density measurement, and determination of the volume fraction of WC particles are performed throughout the castings using both image analysis and optical microscopy. The effects of particle filling on mechanical properties are first evaluated through a microhardness survey of the castings. The volume fraction of WC particles is validated using a thorough density survey and a rule-of-mixtures model. Split Hopkinson Pressure Bar (SHPB) testing of various volume fraction specimens is conducted to determine strain dependence of mechanical properties and to compare the process-property relationships between the two casting techniques. The baseline performances of C95400 bronze are provided for comparison. The results show that the addition of WC particles improves microhardness significantly for the centrifugally cast specimens, and, to a lesser extent, in the sedimentation-cast specimens, largely because the WC particles are more concentrated as a result of the centrifugal-casting process. Both metal matrix composites (MMCs) demonstrate strain rate dependency, with sedimentation casting having a greater, but variable, effects on material response. This difference is attributed to legacy effects from the casting process, namely, porosity and localized WC particle grouping. Content Type Journal Article Pages 1-6 DOI 10.1007/s11665-011-9996-y Authors Lloyd Brown, Mechanical Engineering Department, US Naval Academy, 590 Holloway Road, Annapolis, MD 21402, USA Peter Joyce, Mechanical Engineering Department, US Naval Academy, 590 Holloway Road, Annapolis, MD 21402, USA Joshua Radice, Mechanical Engineering Department, US Naval Academy, 590 Holloway Road, Annapolis, MD 21402, USA Dro Gregorian, Mechanical Engineering Department, US Naval Academy, 590 Holloway Road, Annapolis, MD 21402, USA Michael Gobble, United States Marine Corps, Quantico, VA, USA Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    The exfoliation corrosion (EXCO) behavior of Al-Zn-Mg-Cu-Cr alloy after severe cold rolling was investigated by optical microscope, transmission electron microscope, and electrochemical technique. The results show that the EXCO resistance decreased with increasing cold rolling reduction because of the grain boundaries which were decorated with the continuously distributed particles . After the solution treatment, the samples with different reductions retained the fibrous grains, and the elongated grains accelerated the growth of the corrosion cracks according to crack propagation analysis. Furthermore, the increase of deformation enhanced the degree of recrystallization, while the number of corrosion cells increased greatly when in the electrolyte, which tended to reduce the resistance to EXCO. Content Type Journal Article Pages 1-6 DOI 10.1007/s11665-011-9978-0 Authors Lianghua Lin, Key Laboratory of Nonferrous Metal Materials Science and Engineering, Ministry of Education, Central South University, Changsha, 410083 People’s Republic of China Zhiyi Liu, Key Laboratory of Nonferrous Metal Materials Science and Engineering, Ministry of Education, Central South University, Changsha, 410083 People’s Republic of China Yao Li, School of Material Science and Engineering, Central South University, Changsha, 410083 People’s Republic of China Xiangnan Han, School of Material Science and Engineering, Central South University, Changsha, 410083 People’s Republic of China Xu Chen, School of Material Science and Engineering, Central South University, Changsha, 410083 People’s Republic of China Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    Cutting tools have an important role in the machining process, since they are related to workpiece surface quality and production costs. Due to the importance of selecting appropriate cutting parameters during the milling process, this research develops empirical expressions to predict the tool wear mechanisms that a cutting tool will suffer during the milling of AISI 1045. In addition, an expression to predict the critical cutting speed value where the diffusion mechanism starts to appear is developed. AISI 1045 was selected as the workpiece material due to its excellent machinability, good abrasion resistance, and mechanical strength. The Design of Experiments method namely Taguchi was applied to reduce the time and cost of experiments. The results showed that the cutting speed is the parameter with the most influence on tool flank wear which started to appear when using V  = 500 m/min and the diffusion tool wear mechanism at V  = 850 m/min. Content Type Journal Article Pages 1-12 DOI 10.1007/s11665-011-9964-6 Authors Patricia Muñoz-Escalona, Universidad Simón Bolívar, Mecánica, Edf. Meu. 3er Piso. Valle de Sartenejas, Caracas, 1080 Venezuela Nayarit Díaz, Universidad Simón Bolívar, Mecánica, Edf. Meu. 3er Piso. Valle de Sartenejas, Caracas, 1080 Venezuela Zulay Cassier, Universidad Simón Bolívar, Mecánica, Edf. Meu. 3er Piso. Valle de Sartenejas, Caracas, 1080 Venezuela Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    A non-equilibrium molecular dynamics method is employed to study the mechanical response of soda-lime glass (a material commonly used in transparent armor applications) when subjected to the loading conditions associated with the generation and propagation of planar shock waves. Specific attention is given to the identification and characterization of various (inelastic-deformation and energy-dissipation) molecular-level phenomena and processes taking place at, or in the vicinity of, the shock front. The results obtained revealed that the shock loading causes a 2-4% (shock strength-dependent) density increase. In addition, an increase in the average coordination number of the silicon atoms is observed along with the creation of smaller Si-O rings. These processes are associated with substantial energy absorption and dissipation and are believed to greatly influence the blast/ballistic impact mitigation potential of soda-lime glass. The present work was also aimed at the determination of the shock Hugoniot (i.e., a set of axial stress vs. density/specific-volume vs. internal energy vs. particle velocity vs. temperature) material states obtained in soda-lime glass after the passage of a shock wave of a given strength (as quantified by the shock speed). The availability of a shock Hugoniot is critical for construction of a high deformation-rate, large-strain, high pressure material model which can be used within a continuum-level computational analysis to capture the response of a soda-lime glass based laminated transparent armor structure (e.g., a military vehicle windshield, door window, etc.) to blast/ballistic impact loading. Content Type Journal Article Pages 1-11 DOI 10.1007/s11665-011-0064-4 Authors M. Grujicic, Department of Mechanical Engineering, Clemson University, 241 Engineering Innovation Building, Clemson, SC 29634-0921, USA W. C. Bell, Department of Mechanical Engineering, Clemson University, 241 Engineering Innovation Building, Clemson, SC 29634-0921, USA B. Pandurangan, Department of Mechanical Engineering, Clemson University, 241 Engineering Innovation Building, Clemson, SC 29634-0921, USA B. A. Cheeseman, Army Research Laboratory – Survivability Materials Branch, Aberdeen, Proving Ground, MD 21005-5069, USA C. Fountzoulas, Army Research Laboratory – Survivability Materials Branch, Aberdeen, Proving Ground, MD 21005-5069, USA P. Patel, Army Research Laboratory – Survivability Materials Branch, Aberdeen, Proving Ground, MD 21005-5069, USA Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    Experiments were carried out using carbide turning inserts on AA7075/10 wt.% SiC (particle size 10-20 μm) composites to get actual input values to the optimization problem, so that the optimized results are realistic. By using experimental data, the regression model was developed. This model was used to formulate the fitness function of the genetic algorithm (GA). This investigation attempts to perform the application of GA for finding the optimal solution of the cutting conditions minimum value of surface roughness. The analysis of this investigation shows that the GA technique is capable of estimating the optimal cutting conditions that yield the minimum surface roughness value. With the highest speed, the lowest feed rate, the lowest depth of cut, and the highest nose radius of the cutting conditions' scale, the GA technique recommends 1.039 μm as the best minimum predicted surface roughness value. This means that the GA technique has decreased the minimum surface roughness value of the experimental sample data, regression modeling and desirability analysis by about 3%, 1%, and 2.8%, respectively. Content Type Journal Article Pages 1-11 DOI 10.1007/s11665-011-0066-2 Authors Rajesh Kumar Bhushan, Shri Mata Vaishno Devi University, Katra, Jammu, J&K, India Sudhir Kumar, Noida Institute of Engineering &Technology, Greater Noida, India S. Das, Advanced Materials & Processes Research Institute, Bhopal, India Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    Fine holes in metal alloys are employed for many important technological purposes, including cooling and the precise atomization of liquids. For example, they play an important role in the metering and delivery of fuel to the combustion chambers in energy-efficient, low-emission diesel engines. Electro-discharge machining (EDM) is one process employed to produce such holes. Since the hole shape and bore morphology can affect fluid flow, and holes also represent structural discontinuities in the tips of the spray nozzles, it is important to understand the microstructures adjacent to these holes, the features of the hole walls, and the nanomechanical properties of the material that was in some manner altered by the EDM hole-making process. Several techniques were used to characterize the structure and properties of spray-holes in a commercial injector nozzle. These include scanning electron microscopy, cross sectioning and metallographic etching, bore surface roughness measurements by optical interferometry, scanning electron microscopy, and transmission electron microscopy of recast EDM layers extracted with the help of a focused ion beam. Content Type Journal Article Pages 1-7 DOI 10.1007/s11665-011-0070-6 Authors P. J. Blau, Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA J. Y. Howe, Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA D. W. Coffey, Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA R. M. Trejo, Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA E. D. Kenik, Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA B. C. Jolly, Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA N. Yang, Caterpillar Inc., Peoria, IL, USA Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    Spallation is a fracture mode commonly observed in ballistically/blast-wave-loaded structures. The interaction between decompression waves generated within the target structure produces tensile stresses which, if of a sufficient magnitude, may cause material damage and ultimate fracture (spallation). In this study, the phenomenon of spall-fracture is analyzed within a one-dimensional Lagrangian framework. Two distinct analyses are carried out. Within the first analysis, decompression waves are treated as decompression shocks, which simplified the analysis and enabled the formation of spallation-strength-based material index. In the second analysis, decompression waves are treated as smooth (centered simple) waves. This increased the fidelity of the computational analysis, but the material-selection procedure could be done only numerically and an explicit formulation of the spallation-strength-based material-selection index could not be carried out. Overall, the two analyses yielded similar results for the spallation-strength-based material-selection criterion suggesting that the simpler (decompression shock based) one is still adequate for use in the material-selection process. Content Type Journal Article Pages 1-11 DOI 10.1007/s11665-011-0068-0 Authors M. Grujicic, Department of Mechanical Engineering, Clemson University, 241 Engineering Innovation Building, Clemson, SC 29634-0921, USA B. Pandurangan, Department of Mechanical Engineering, Clemson University, 241 Engineering Innovation Building, Clemson, SC 29634-0921, USA B. A. Cheeseman, Army Research Laboratory—Survivability Materials Branch, Aberdeen, Proving Ground, MD 21005-5069, USA C.-F. Yen, Army Research Laboratory—Survivability Materials Branch, Aberdeen, Proving Ground, MD 21005-5069, USA Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    The effects of hydrogen and surface finish on the mean low cycle fatigue life of Haynes 188 were studied. Specimens were prepared and fatigue tested with gage sections having low stress ground (LSG) and electro-discharge machined (EDM) surfaces. Fatigue tests were performed at temperatures of 25 to 650 °C with varied strain conditions, in hydrogen and helium environments. Fatigue life decreased with increasing strain range, strain ratio, temperature, and with hydrogen atmosphere. A Smith-Watson-Topper stress parameter could be used to account for variations in strain range and strain ratio, and most strongly influenced life. Hydrogen reduced fatigue life by about 5× (80%) at 25 °C, but was much less harmful at 650 °C. Standard EDM finish did not consistently reduce mean fatigue life from that of LSG finish specimens. Additional tests indicated fatigue life in hydrogen was maintained for varied EDM conditions, provided specimen roughness and maximum recast layer thickness were not excessive. Content Type Journal Article Pages 1-9 DOI 10.1007/s11665-011-0067-1 Authors T. P. Gabb, NASA Glenn Research Center, 21000 Brookpark Rd., Cleveland, OH 44135, USA H. Webster, ATK Missile Products Group, 300 Village Square Crossing, Suite 201, Palm Beach Gardens, FL 33410, USA G. Ribeiro, ATK Missile Products Group, 300 Village Square Crossing, Suite 201, Palm Beach Gardens, FL 33410, USA T. Gorman, University of Dayton, 300 College Park, Dayton, OH 45469, USA J. Gayda, NASA Glenn Research Center, 21000 Brookpark Rd., Cleveland, OH 44135, USA Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    The heat-affected zone (HAZ) is generally the intrinsic weakest location of the normal friction stir welded precipitate hardened aluminum alloys. In order to improve the mechanical properties of the HAZ by controlling the temperature level, underwater friction stir welding (FSW) of an Al-Cu aluminum alloy was conducted in the present study. The results indicate that the hardness of the HAZ can be improved through underwater FSW. Microstructural analysis reveals that the hardness improvement is attributed to the lowering of precipitate coarsening level and the narrowing of precipitate free zone, which are essentially induced by the variations of welding thermal cycles under the cooling effect of water. Content Type Journal Article Pages 1-6 DOI 10.1007/s11665-011-0060-8 Authors H. J. Zhang, State Key Laboratory of Advanced Welding Production Technology, Harbin Institute of Technology, Harbin, 150001 People’s Republic of China H. J. Liu, State Key Laboratory of Advanced Welding Production Technology, Harbin Institute of Technology, Harbin, 150001 People’s Republic of China L. Yu, State Key Laboratory of Advanced Welding Production Technology, Harbin Institute of Technology, Harbin, 150001 People’s Republic of China Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    Workpiece material flow and stirring/mixing during the friction stir welding (FSW) process are investigated computationally. Within the numerical model of the FSW process, the FSW tool is treated as a Lagrangian component while the workpiece material is treated as an Eulerian component. The employed coupled Eulerian/Lagrangian computational analysis of the welding process was of a two-way thermo-mechanical character (i.e., frictional-sliding/plastic-work dissipation is taken to act as a heat source in the thermal-energy balance equation) while temperature is allowed to affect mechanical aspects of the model through temperature-dependent material properties. The workpiece material (AA5059, solid-solution strengthened and strain-hardened aluminum alloy) is represented using a modified version of the classical Johnson-Cook model (within which the strain-hardening term is augmented to take into account for the effect of dynamic recrystallization) while the FSW tool material (AISI H13 tool steel) is modeled as an isotropic linear-elastic material. Within the analysis, the effects of some of the FSW key process parameters are investigated (e.g., weld pitch, tool tilt-angle, and the tool pin-size). The results pertaining to the material flow during FSW are compared with their experimental counterparts. It is found that, for the most part, experimentally observed material-flow characteristics are reproduced within the current FSW-process model. Content Type Journal Article Pages 1-17 DOI 10.1007/s11665-011-0069-z Authors M. Grujicic, Department of Mechanical Engineering, Clemson University, 241 Engineering Innovation Building, Clemson, SC 29634-0921, USA G. Arakere, Department of Mechanical Engineering, Clemson University, 241 Engineering Innovation Building, Clemson, SC 29634-0921, USA B. Pandurangan, Department of Mechanical Engineering, Clemson University, 241 Engineering Innovation Building, Clemson, SC 29634-0921, USA J. M. Ochterbeck, Department of Mechanical Engineering, Clemson University, 241 Engineering Innovation Building, Clemson, SC 29634-0921, USA C-F. Yen, Army Research Laboratory—Survivability Materials Branch, Aberdeen, Proving Ground, MD 21005-5069, USA B. A. Cheeseman, Army Research Laboratory—Survivability Materials Branch, Aberdeen, Proving Ground, MD 21005-5069, USA A. P. Reynolds, Department of Mechanical Engineering, University of South Carolina, Columbia, SC 29208, USA M. A. Sutton, Department of Mechanical Engineering, University of South Carolina, Columbia, SC 29208, USA Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    In automotive a lot of electromagnetically, pyrotechnically or mechanically driven actuators are integrated to run comfort systems and to control safety systems in modern passenger cars. Using shape memory alloys (SMA) the existing systems could be simplified, performing the same function through new mechanisms with reduced size, weight, and costs. A drawback for the use of SMA in safety systems is the lack of materials knowledge concerning the durability of the switching function (long-time stability of the shape memory effect). Pedestrian safety systems play a significant role to reduce injuries and fatal casualties caused by accidents. One automotive safety system for pedestrian protection is the bonnet lifting system. Based on such an application, this article gives an introduction to existing bonnet lifting systems for pedestrian protection, describes the use of quick changing shape memory actuators and the results of the study concerning the long-time stability of the tested NiTi-wires. These wires were trained, exposed up to 4 years at elevated temperatures (up to 140 °C) and tested regarding their phase change temperatures, times, and strokes. For example, it was found that A P -temperature is shifted toward higher temperatures with longer exposing periods and higher temperatures. However, in the functional testing plant a delay in the switching time could not be detected. This article gives some answers concerning the long-time stability of NiTi-wires that were missing till now. With this knowledge, the number of future automotive applications using SMA can be increased. It can be concluded, that the use of quick changing shape memory actuators in safety systems could simplify the mechanism, reduce maintenance and manufacturing costs and should be insertable also for other automotive applications. Content Type Journal Article Pages 1-5 DOI 10.1007/s11665-011-9848-9 Authors Joachim Strittmatter, WITg Institut für Werkstoffsystemtechnik Thurgau an der Hochschule Konstanz, CH-8274 Tägerwilen, Switzerland Paul Gümpel, WITg Institut für Werkstoffsystemtechnik Thurgau an der Hochschule Konstanz, CH-8274 Tägerwilen, Switzerland Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    In the light of attractive wear characteristics as well as high strength to weight ratio, extensive research on Al-based Metal Matrix Composite (MMC) have been carried out globally in the last two decades. However, very limited research has been pursued on tribological behavior of Al-based MMC under combined action of rolling and sliding. This study investigates the wear behavior of 6061 Al-alloy/SiC with 10 vol.% SiCp against hardened and tempered AISI 4340 steel under combined rolling-sliding conditions. 2 3 factorial design of experiments have been carried out to see the effect of few parameters, i.e., contact stress, speed and duration with respect to wear. The interaction effect has also been studied by 3D graphical contours. A mathematical model is developed using regression analysis technique for prediction of wear behavior of the MMC and adequacy of the model has been validated using analysis of variance (ANOVA) techniques. Finally, the optimization of parameter has also been done using Design Expert software. The results have shown that Response Surface Methodology (RSM) is an effective tool for prediction of wear behavior under combined sliding and rolling action. It is also found that the wear of MMC is much lower than hardened; tempered AISI 4340 steel and rolling speed has the maximum influence in wear of both materials under investigation. Content Type Journal Article Pages 1-8 DOI 10.1007/s11665-011-9890-7 Authors Nilrudra Mandal, Centre for Advanced Material Processing, Central Mechanical Engineering Research Institute, Council of Scientific and Industrial Research (CSIR), M.G. Avenue, Durgapur, 713209 India H. Roy, NDT & Metallurgy Group, Central Mechanical Engineering Research Institute, Council of Scientific and Industrial Research (CSIR), M.G. Avenue, Durgapur, 713209 India B. Mondal, Centre for Advanced Material Processing, Central Mechanical Engineering Research Institute, Council of Scientific and Industrial Research (CSIR), M.G. Avenue, Durgapur, 713209 India N. C. Murmu, Surface Engineering & Tribology Group, Central Mechanical Engineering Research Institute, Council of Scientific and Industrial Research (CSIR), M.G. Avenue, Durgapur, 713209 India S. K. Mukhopadhyay, NDT & Metallurgy Group, Central Mechanical Engineering Research Institute, Council of Scientific and Industrial Research (CSIR), M.G. Avenue, Durgapur, 713209 India Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    In this article, an advanced laminated composite is developed, combining the high damping properties of shape memory alloy (SMA) with mechanical properties and light weight of a glass-fiber reinforced polymer. The composite is formed by stacking a glass-fiber reinforced epoxy core between two thin patterned strips of SMA alloy, and two further layers of fiber-glass reinforced epoxy. The bars of the laminated composite were assembled and cured in autoclave. The patterning was designed to enhance the interface adhesion between matrix and SMA inserts and optimally exploit the damping capacity of the SMA thin ribbons. The patterned ribbons of the SMA alloy were cut by means of a pulsed fiber laser source. Damping properties at different amplitudes on full scale samples were investigated at room temperature with a universal testing machine through dynamic tension tests, while temperature dependence was investigated by dynamic mechanical analyses (DMA) on smaller samples. Experimental results were used in conjunction with FEM analysis to optimize the geometry of the inserts. Experimental decay tests on the laminated composite have been carried out to identify the adimensional damping value related to their first flexural mode. Content Type Journal Article Pages 1-8 DOI 10.1007/s11665-011-9887-2 Authors S. Arnaboldi, CNR Institute for Energetics and Interphases, Corso Promessi Sposi, 29, Lecco, Italy P. Bassani, CNR Institute for Energetics and Interphases, Corso Promessi Sposi, 29, Lecco, Italy C. A. Biffi, CNR Institute for Energetics and Interphases, Corso Promessi Sposi, 29, Lecco, Italy A. Tuissi, CNR Institute for Energetics and Interphases, Corso Promessi Sposi, 29, Lecco, Italy M. Carnevale, Department of Mechanical Engineering, Politecnico di Milano, Via La Masa, 34, Milan, Italy N. Lecis, Department of Mechanical Engineering, Politecnico di Milano, Via La Masa, 34, Milan, Italy A. LoConte, Department of Mechanical Engineering, Politecnico di Milano, Via La Masa, 34, Milan, Italy B. Previtali, Department of Mechanical Engineering, Politecnico di Milano, Via La Masa, 34, Milan, Italy Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    This article reports the influences of welding speed on tensile properties of the friction stir welded AZ61A magnesium alloy. Five different welding speeds ranging from 30 to 150 mm/min were used to fabricate the joints. Tensile properties of the joints were evaluated and correlated with the stir zone microstructure and hardness. From this investigation, it is found that the joint fabricated with a welding speed of 90 mm/min exhibited the acceptable tensile properties compared to other joints. The formation of fine grains in the stir zone is the main reason for the higher hardness and acceptable tensile properties of these joints. Content Type Journal Article Pages 1-9 DOI 10.1007/s11665-011-9889-0 Authors A. Razal Rose, Department of Mechanical Engineering, National Engineering College, K.R Nagar, Kovilpatti, 628 503 Tamil Nadu India K. Manisekar, Centre for Manufacturing Sciences, National Engineering College, K.R Nagar, Kovilpatti, 628 503 Tamil Nadu India V. Balasubramanian, Department of Manufacturing Engineering, Annamalai University, Annamalainagar, Chidambaram, 608 002 Tamil Nadu India Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    Nitinol self-expanding stents are used to treat peripheral occluded vessels such as the superficial femoral artery or the carotid. The complex vessel articulation requires a stent device that is flexible and kink resistant yet durable. The present study shows how the latest advances in commercially available engineering software tools permit engineering simulations of the many aspects of the Nitinol stent design and analysis. Two stent geometries are evaluated: a helical type stent design, and a more traditional straight strut, with multiple crowns design. The fatigue performance of the two stents is compared. The results show that advanced nonlinear finite element simulations and fatigue predictions of the Nitinol stent are possible today inside realistic simulated human arteries. The finite element analysis software used in this study is SimXpert, Marc, and Mentat (MSC Software, Santa Ana, CA). Content Type Journal Article Pages 1-9 DOI 10.1007/s11665-011-9881-8 Authors Sean Michael Harvey, MSC Software Corporation, Santa Ana, CA USA Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    Laser cutting and wire forming are two of the most commonly used processes in the manufacture of Nitinol medical devices. This study explores how varying the amount of material removed during the final surface treatment steps affects the corrosion resistance of Z-type stents that have either been laser-cut from tube or shape set from wire. All parts were subjected to a typical heat treatment process necessary to achieve an Austenite finish (A f ) temperature of 25 ± 5 °C, and were subsequently post-processed with an electrochemical passivation process. The total weight loss during post-processing was recorded and the process adjusted to create groups with less than 5%, less than 10%, and less than 25% amounts of weight loss. The parts were then crimped to 6 mm and allowed to expand back to their original diameter. The corrosion test results showed that on average both groups of Z-stents experienced an increase in the corrosion breakdown potential and a decrease in the standard deviation with increasing amounts of material removal. In addition, less material removal is required from the wire-form Z-stents as compared to the laser-cut Z-stents to achieve high corrosion resistance. Finally, 7 day nickel ion release tests performed on the wire-formed Z-stents showed a dramatic decrease from 0.0132 mg of nickel leached per day for the low weight loss group to approximately 0.001 mg/day for the medium and high weight loss groups. Content Type Journal Article Pages 1-5 DOI 10.1007/s11665-011-9882-7 Authors Jennifer Fino Decker, Nitinol Devices and Components, 47533 Westinghouse Drive, Fremont, CA USA Christine Trépanier, Nitinol Devices and Components, 47533 Westinghouse Drive, Fremont, CA USA Lot Vien, Nitinol Devices and Components, 47533 Westinghouse Drive, Fremont, CA USA Alan R. Pelton, Nitinol Devices and Components, 47533 Westinghouse Drive, Fremont, CA USA Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    Most implantable medical devices are expected to function in the body over an extended period of time. Therefore, immersion tests under simulated conditions can be useful for assessing the amount of metal ions released in situ. In this investigation, dissolved ions from as-received binary and ternary Nitinol alloys in cell culture media were periodically measured under static and dynamic conditions. Endothelial cells were grown in aliquots of culture media obtained and the effect of dissolved ions on cell proliferation and viability of endothelial cells (HUVEC) was studied by cytotoxicity assays. The concentration of metal ions in the media was measured by inductively coupled plasma mass spectrometry. Content Type Journal Article Pages 1-3 DOI 10.1007/s11665-011-9884-5 Authors W. Haider, Department of Materials Science and Engineering, Penn State University, University Park, PA USA N. Munroe, Applied Research Center, Florida International University, Miami, FL USA V. Tek, Applied Research Center, Florida International University, Miami, FL USA P. K. S. Gill, Applied Research Center, Florida International University, Miami, FL USA Y. Tang, Department of Biomedical Engineering, Florida International University, Miami, FL USA A. J. McGoron, Department of Biomedical Engineering, Florida International University, Miami, FL USA Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    Development of a superelastic material with higher stiffness and plateau stresses than binary nitinol is of interest to the medical device industry because it may allow for lower profile, less intrusive devices without compromising the material’s characteristics. This project studied the effect of cobalt (Co) alloying additions on the stiffness and plateau stresses of a superelastic nickel-titanium alloy. In addition, the general physical, mechanical, corrosion, and biocompatibility properties of the alloy were compared to binary nitinol. The results of this study showed Co to be an interesting alloying addition that should be considered for future medical devices in applications, where stiffness is of concern. Content Type Journal Article Pages 1-5 DOI 10.1007/s11665-011-9845-z Authors Audrey Fasching, SAES Memry Corporation, Bethel, CT USA D. Norwich, SAES Memry Corporation, Bethel, CT USA T. Geiser, SAES Memry Corporation, Bethel, CT USA Graeme W. Paul, SAES Smart Materials, New Hartford, NY USA Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    Shape memory alloys (SMAs) are smart materials exploited in many applications to build actuators with high power to mass ratio. Typical SMA drawbacks are: wires show poor stroke and excessive length, helical springs have limited mechanical bandwidth and high power consumption. This study is focused on the design of a large-scale linear SMA actuator conceived to maximize the stroke while limiting the overall size and the electric consumption. This result is achieved by adopting for the actuator a telescopic multi-stage architecture and using SMA helical springs with hollow cross section to power the stages. The hollow geometry leads to reduced axial size and mass of the actuator and to enhanced working frequency while the telescopic design confers to the actuator an indexable motion, with a number of different displacements being achieved through simple on-off control strategies. An analytical thermo-electro-mechanical model is developed to optimize the device. Output stroke and force are maximized while total size and power consumption are simultaneously minimized. Finally, the optimized actuator, showing good performance from all these points of view, is designed in detail. Content Type Journal Article Pages 1-8 DOI 10.1007/s11665-011-9872-9 Authors Andrea Spaggiari, Department of Engineering Science and Methods, University of Modena and Reggio Emilia, via Amendola, 2, 42122 Reggio Emilia, Italy Igor Spinella, Department of Engineering Science and Methods, University of Modena and Reggio Emilia, via Amendola, 2, 42122 Reggio Emilia, Italy Eugenio Dragoni, Department of Engineering Science and Methods, University of Modena and Reggio Emilia, via Amendola, 2, 42122 Reggio Emilia, Italy Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    Numerous experimental investigations reported in the open literature over the past decade have clearly demonstrated that the use of polyurea external coatings and/or inner layers can substantially enhance both the blast resistance (the ability to withstand shock loading) and the ballistic performance (the ability to defeat various high-velocity projectiles such as bullets, fragments, shrapnel, etc. without penetration, excessive deflection or spalling) of buildings, vehicles, combat-helmets, etc. It is also well established that the observed high-performance of polyurea is closely related to its highly complex submicron scale phase-segregated microstructure and the associated microscale phenomena and processes (e.g., viscous energy dissipation at the internal phase boundaries). As higher and higher demands are placed on blast/ballistic survivability of the foregoing structures, a need for the use of the appropriate transient nonlinear dynamics computational analyses and the corresponding design-optimization methods has become ever apparent. A critical aspect of the tools used in these analyses and methods is the availability of an appropriate physically based, high-fidelity material model for polyurea. There are presently several public domain and highly diverse material models for polyurea. In the present work, an attempt is made to critically assess these models as well as the experimental methods and results used in the process of their formulation. Since these models are developed for use in the high-rate loading regime, they are employed in the present work, to generate the appropriate shock-Hugoniot relations. These relations are subsequently compared with their experimental counterparts in order to assess the fidelity of these models. Content Type Journal Article Pages 1-15 DOI 10.1007/s11665-011-9875-6 Authors M. Grujicic, Department of Mechanical Engineering, Clemson University, 241 Engineering Innovation Building, Clemson, SC 29634-0921, USA T. He, Department of Mechanical Engineering, Clemson University, 241 Engineering Innovation Building, Clemson, SC 29634-0921, USA B. Pandurangan, Department of Mechanical Engineering, Clemson University, 241 Engineering Innovation Building, Clemson, SC 29634-0921, USA F. R. Svingala, Department of Mechanical Engineering, Pennsylvania State University, University Park, PA 16082, USA G. S. Settles, Department of Mechanical Engineering, Pennsylvania State University, University Park, PA 16082, USA M. J. Hargather, Department of Mechanical Engineering, Pennsylvania State University, University Park, PA 16082, USA Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    In the recent years, the research for novel materials with tailored mechanical properties, as well as functional properties, has encouraged the study of porous and cellular materials. Our previous work proposed and reported about the possibility to manufacture open-cell metal foams of CuZnAl shape memory alloy by liquid infiltration in a leachable bed of silica-gel particles. This innovative methodology is based on cheap commercial consumables and a simple technology, focusing on intermediate-density low-cost foams with interesting cost/benefits ratio. Microstructural analyses on foamed specimens showed uniform microstructure of ligaments and a very regular and well reproducible open-cell morphology. Moreover, calorimetric analysis detected a thermo-elastic martensitic transformation in the foamed material. In this study, a CuZnAl shape memory alloy was considered and tested to clarify possible effects of the foaming process on the functional properties of the material. Morphological, calorimetric, and thermo-mechanical analyses were carried out. The results show that it is possible to produce metal foams of CuZnAl shape memory alloy with different functional properties and able to recover mono-axial compressive strains up to 3%. Content Type Journal Article Pages 1-7 DOI 10.1007/s11665-011-9878-3 Authors S. Arnaboldi, Institute for Energetics and Interphases, Corso Promessi Sposi 29, Lecco, Italy P. Bassani, Institute for Energetics and Interphases, Corso Promessi Sposi 29, Lecco, Italy F. Passaretti, Institute for Energetics and Interphases, Corso Promessi Sposi 29, Lecco, Italy A. Redaelli, Institute for Energetics and Interphases, Corso Promessi Sposi 29, Lecco, Italy A. Tuissi, Institute for Energetics and Interphases, Corso Promessi Sposi 29, Lecco, Italy Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    The introduction of newer joining technologies like the so-called friction-stir welding (FSW) into automotive engineering entails the knowledge of the joint-material microstructure and properties. Since, the development of vehicles (including military vehicles capable of surviving blast and ballistic impacts) nowadays involves extensive use of the computational engineering analyses (CEA), robust high-fidelity material models are needed for the FSW joints. A two-level material-homogenization procedure is proposed and utilized in this study to help manage computational cost and computer storage requirements for such CEAs. The method utilizes experimental (microstructure, microhardness, tensile testing, and x-ray diffraction) data to construct: (a) the material model for each weld zone and (b) the material model for the entire weld. The procedure is validated by comparing its predictions with the predictions of more detailed but more costly computational analyses. Content Type Journal Article Pages 1-11 DOI 10.1007/s11665-011-9876-5 Authors M. Grujicic, Department of Mechanical Engineering, Clemson University, 241 Engineering Innovation Building, Clemson, SC 29634-0921, USA G. Arakere, Department of Mechanical Engineering, Clemson University, 241 Engineering Innovation Building, Clemson, SC 29634-0921, USA A. Hariharan, Department of Mechanical Engineering, Clemson University, 241 Engineering Innovation Building, Clemson, SC 29634-0921, USA B. Pandurangan, Department of Mechanical Engineering, Clemson University, 241 Engineering Innovation Building, Clemson, SC 29634-0921, USA Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    Ti alloys have been widely used in the aerospace, chemical, and biomedical industries for their high strength/weight ratio and corrosion resistance. However, Nitinol’s usage in the latter industry has been fraught with concerns of allergic and toxic effects of Ni released from implants. Recently, much attention has been placed on the development of Ni-free Ti-Ta alloys, which are considered prime candidates for applications such as metal-on-metal spinal disk replacements, orthopedic implants, cardiovascular stents, dental posts, and guide wires. In this research, the biocompatibility of Ti-30Ta alloys manufactured by powder metallurgy (PM) and arc melting (ARC) were investigated. The corrosion resistance of each alloy was determined in accordance with ASTM F 2129-08 in phosphate buffered saline (PBS) and PBS with amino acids at 37 °C. The concentration of metal ions released during corrosion was measured by Inductively Coupled Plasma Mass Spectroscopy (ICP-MS). Scanning Electron Microscopy (SEM) was used to assess the morphology of the alloys before and after corrosion. Vicker’s hardness tests were performed to compare the hardness and tensile strength of the alloys. Human osteoblast cells were successfully grown on the surface of both alloys. Content Type Journal Article Pages 1-5 DOI 10.1007/s11665-011-9874-7 Authors P. Gill, Mechanical and Materials Engineering Department, Florida International University, Miami, FL USA N. Munroe, Mechanical and Materials Engineering Department, Florida International University, Miami, FL USA C. Pulletikurthi, Mechanical and Materials Engineering Department, Florida International University, Miami, FL USA S. Pandya, Mechanical and Materials Engineering Department, Florida International University, Miami, FL USA W. Haider, Materials Science and Engineering, Penn State University, University Park, PA USA Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    Comminuted and displaced fractures of the inferior pole of the patella are not easy to reduce and it is difficult to fix the fragments soundly enough to allow early movement of the knee. The purpose of this study is to evaluate the clinical effectiveness of the internal fixation technique with Patellar Shape-Memory Fixator (PSMF) in acute comminuted fractures of the inferior pole of the patella. We retrospectively studied 25 patients with comminuted fractures of the inferior pole of the patella who were treated with PSMF and followed up for a mean period of 26 months (14 to 60). All the fractures healed at a mean of 6 weeks (5 to 7). The mean grading at the final follow-up was 29.5 points (27 to 30) using the Bostman score, with no observable restriction of movement. No breakage of the PSMF or infection occurred. No delayed union, nonunion, and infection were seen. This technique preserved the length of the patella, reduced the comminuted fragments of the inferior pole and avoided long-term immobilization of the knee. Content Type Journal Article Pages 1-6 DOI 10.1007/s11665-011-9862-y Authors Xin-Wei Liu, Department of Orthopaedic Surgery, PLA No. 210 Hospital, Xigang District, Dalian, Liaoning Province China Hui-Juan Shang, Department of Orthopaedic Surgery, PLA No. 210 Hospital, Xigang District, Dalian, Liaoning Province China Shuo-Gui Xu, Department of Orthopaedic Surgery, Changhai Hospital, The Second Military Medical University, Shanghai, 200433 China Zhi-Wei Wang, Department of Orthopaedic Surgery, Changhai Hospital, The Second Military Medical University, Shanghai, 200433 China Chun-Cai Zhang, Department of Orthopaedic Surgery, Changhai Hospital, The Second Military Medical University, Shanghai, 200433 China Qing-Ge Fu, Department of Orthopaedic Surgery, Changhai Hospital, The Second Military Medical University, Shanghai, 200433 China Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    The fracture behaviors of the 7075 aluminum alloy under two different dynamic loading conditions are investigated by means of a light-gas gun. The fracture surfaces obtained in the spall test are compared to the fracture surfaces obtained with a blunt projectile struck to the aluminum alloy plate. Optical and scanning electron microscopes are used in the investigation. For the plate-impact test, spall of the target was attributed to intergranular fracture caused by the tensile stress. The fracture behavior during projectile penetration is complex and consists of several fracture modes in addition to that the fracture is also of dynamic character. The penetration process of aluminum alloy target included: plugging stage, the microcracks nucleation stage, and the final tensile fracture stage. Mixed intergranular brittle/ductile fracture was observed, and brittle fracture played a dominate role. Content Type Journal Article Pages 1-5 DOI 10.1007/s11665-011-9879-2 Authors Yang Yang, School of Materials Science and Engineering, Central South University, Changsha, 410083 Hunan People’s Republic of China Xiaoming Li, School of Materials Science and Engineering, Central South University, Changsha, 410083 Hunan People’s Republic of China Chengyuan Xu, School of Materials Science and Engineering, Central South University, Changsha, 410083 Hunan People’s Republic of China Liansheng Zhang, State Key Laboratory of Explosion Science and Technology, Beijing, 100081 People’s Republic of China Qingming Zhang, State Key Laboratory of Explosion Science and Technology, Beijing, 100081 People’s Republic of China Xiaole Tong, School of Materials Science and Engineering, Central South University, Changsha, 410083 Hunan People’s Republic of China Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    Shape memory alloys (SMAs) are thermally activated smart materials. Due to their ability to change into a previously imprinted shape by the means of thermal activation, they are suitable as actuators for microsystems and, within certain limitations for macroscopic systems. Most commonly used SMAs for actuators are binary nickel-titanium alloys (NiTi). The shape memory effect relies on the martensitic phase transformation. On heating the material from the low temperature phase (martensite) the material starts to transform into the high temperature phase (austenite) at the austenite start temperature ( A s ). The reverse transformation starts at the martensite start temperature after passing a hysteresis cycle. To apply these materials to a wide range of industrial applications, a simple method for controlling the actuator effect is required. Today’s control concepts for shape memory actuators, in applications as well as in test stands, are time-based. This often leads to overheating after transformation into the high temperature phase which results in early fatigue. Besides, the dynamic behavior of such systems is influenced by unnecessary heating, resulting in a poor time performance. To minimize these effects, a controller system with resistance feedback is required to hold the energy input on specific keypoints. These two key points are directly before transformation ( A s ) and shortly before retransformation ( M s ). This allows triggering of fast and energy-efficient transformation cycles. Both experimental results and a mechatronical demonstrator system, exhibit the advantages of systems concerning efficiency, dynamics, and reliability. Content Type Journal Article Pages 1-5 DOI 10.1007/s11665-011-9877-4 Authors Horst Meier, Ruhr-University Bochum, Universitätsstraße 150 Geb. IB 2/27, 44801 Bochum NRW, Germany Alexander Czechowicz, Ruhr-University Bochum, Universitätsstraße 150 Geb. IB 2/27, 44801 Bochum NRW, Germany Christoph Haberland, Ruhr-University Bochum, Universitätsstraße 150 Geb. IB 2/27, 44801 Bochum NRW, Germany Sven Langbein, Ruhr-University Bochum, Universitätsstraße 150 Geb. IB 2/27, 44801 Bochum NRW, Germany Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    The aim of this investigation was to evaluate the microstructural change after laser welding and its effect on the tensile properties and strain hardening behavior of DP600 and DP980 dual-phase steels. Laser welding led to the formation of martensite and significant hardness rise in the fusion zone because of the fast cooling, but the presence of a soft zone in the heat-affected zone was caused by partial vanishing and tempering of the pre-existing martensite. The extent of softening was much larger in the DP980-welded joints than in the DP600-welded joints. Despite the reduction in ductility, the ultimate tensile strength (UTS) remained almost unchanged, and the yield strength (YS) indeed increased stemming from the appearance of yield point phenomena after welding in the DP600 steel. The DP980-welded joints showed lower YS and UTS than the base metal owing to the appearance of severe soft zone. The YS, UTS, and strain hardening exponent increased slightly with increasing strain rate. While the base metals had multi-stage strain hardening, the welded joints showed only stage III hardening. All the welded joints failed in the soft zone, and the fracture surfaces exhibited characteristic dimple fracture. Content Type Journal Article Pages 1-9 DOI 10.1007/s11665-011-9865-8 Authors N. Farabi, Department of Mechanical and Industrial Engineering, Ryerson University, 350 Victoria Street, Toronto, ON M5B 2K3, Canada D. L. Chen, Department of Mechanical and Industrial Engineering, Ryerson University, 350 Victoria Street, Toronto, ON M5B 2K3, Canada Y. Zhou, Department of Mechanical and Mechatronics Engineering, University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1, Canada Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    A wide range of different thermomechanical treatments was performed on commercially available superelastic Nitinol thin sheet. The ingot composition in the range of standard superelastic material with about 50.8 at.% Ni, balance Ti, was used to manufacture a series of samples with different thermomechanical conditions. Production parameters such as cold work, heat treatment temperature, and heat treatment time were varied. All finished samples were of the same final thickness of 0.3 mm and received the same industrial surface finishing process to obtain a smooth, defect, and oxide-free, shiny surface. Before carrying out the laser cutting, the material was characterized by tensile testing, DSC, and bend-and-free recovery test. Miniature dogbone specimens were cut from the as-manufactured sheets in both directions, longitudinal as well as transverse to the rolling direction. These samples were surface finished using standard deburring and electropolishing processes. For some specific parameter combinations, there were also samples taken at 45° to the rolling direction. All qualified samples were then exposed to fatigue testing in a bending mode until fracture or run-out. The results showed there is a significant effect on the fatigue performance of the samples from both the applied thermomechanical treatment as well as the sheet anisotropy. It is also obvious that the achieved strain data is on average lower than the data obtained in comparable studies on tube or wire, which can be attributed to the different test setup (bending mode in air at 37 °C) as compared to most other studies as well as the larger surface. Content Type Journal Article Pages 1-6 DOI 10.1007/s11665-011-9891-6 Authors Matthias Mertmann, Memry GmbH, Weil am Rhein, Germany Wolfgang Oswald, Memry GmbH, Weil am Rhein, Germany Rainer Steegmüller, Admedes Schuessler GmbH, Pforzheim, Germany Andreas Schüssler, Admedes Schuessler GmbH, Pforzheim, Germany Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    Abrasion-corrosion tests were conducted on two commonly Fe-Cr-C shielded metal arc welding (SMAW) hardfacings used in the sugar industry and an arc sprayed Fe-Cr-based coating. The tests were performed on a modified block-on-ring tester with the coatings sliding against compressed sugarcane fiber in the presence of abrasive slurry. The findings showed that, in the presence of sugarcane juice and sand slurry, the SMAW coatings had similar wear performance while the abrasive wear of the arc-sprayed coating was superior to the SMAW coatings. In the presence of a neutral solution, the material loss from the arc-sprayed coating was similar to that obtained in the sugarcane juice while the SMAW coatings showed a marked decrease; this demonstrated that the arc-sprayed coating was more desirable in an abrasive-corrosion environment. The study also showed that the resistance to material does not follow the expected trend, in which wear resistance increases with increasing hardness. Content Type Journal Article Pages 1-9 DOI 10.1007/s11665-011-9894-3 Authors Vernon E. Buchanan, University of Technology, Jamaica, 237 Old Hope Road, Kingston 6, Jamaica, West Indies Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    Formability of wrought magnesium alloys at room temperature or slightly elevated temperatures is modest, reaching about 20% elongation in a tension test and exhibiting poor resistance to strain localization and failure. The hexagonal close packed structure of Mg has few active slip systems at lower forming temperatures, limiting ductility and reducing applications in auto body structures. Much greater levels of ductility can be reached at higher temperatures (typically 〉300 °C), but this is expensive and inconvenient for a high-volume production environment. Tension testing and biaxial forming of annealed AZ31B magnesium alloy sheets were done at room temperature to various levels of strain. High-resolution electron back scatter diffraction (EBSD) was used to measure twin fraction and dislocation density, in order to find relationships between strain and potential failure locations within the microstructure. Twin fractions were found to have a weak positive correlation to uniaxial and biaxial tensile strain, while dislocation density was found to correlate more strongly with uniaxial tensile strain. Content Type Journal Article Pages 1-7 DOI 10.1007/s11665-011-9897-0 Authors M. P. Miles, Manufacturing Engineering Technology, Brigham Young University, Provo, UT 84602, USA D. Fullwood, Mechanical Engineering, Brigham Young University, Provo, UT 84602, USA B. L. Adams, Mechanical Engineering, Brigham Young University, Provo, UT 84602, USA A. Khosravani, Mechanical Engineering, Brigham Young University, Provo, UT 84602, USA J. Scott, Mechanical Engineering, Brigham Young University, Provo, UT 84602, USA R. K. Mishra, General Motors R&D Center, Warren, MI 48090, USA Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    Based on previous results of bond strength, scanning electron microscopy(SEM)/energy dispersive spectroscopy (EDS) and x-ray photoelectron spectroscopy (for thin film thickness in the range of 50 to 200 nm range), it is expected for a moderate film thickness of titanium (over 50 nm) for the system of sputtered Ti-coated glass/polymer two factors play important roles in getting strong bond between Ti/Polyimide interface: (i) mechanical interlocking property and (ii) chemical bond formation such as Ti-C, Ti-O between Ti and imidex (PI) film. In this study, a systematic investigation has been conducted to understand the effects of thin films on bond quality and on failure mechanism of the interface between 400 nm sputtered Ti-coated glass/imidex (PI) system. This article basically studies if for this higher film thickness the failure pattern and bond strength are consistent with the previous data. From previous studies (for thin film thickness of 50 to 200 nm) the conclusion extracted is thin film with thickness of less than 50 nm exhibited low bond strength when compared to film thickness over 50 nm and from the results obtained in this study it is concluded that the bond reliability and failure modes of sputtered Ti film on glass are consistent even for a film thickness as high as 400 nm and three types of failure modes are found : (i) cohesive failure mode, (ii) Ti/glass interface failure mode, and (iii) glass failure mode. The roughness value for this coating thickness is 17 nm. Content Type Journal Article Pages 1-5 DOI 10.1007/s11665-011-9900-9 Authors Nusrat Lubna, Department of Material Science and Chemical Engineering, Wayne State University, Detroit, MI USA Golam Newaz, Department of Mechanical Engineering, Wayne State University, Detroit, MI USA Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    The feasibility of using SMA wires to improve the seal effectiveness has been studied experimentally and numerically. In this article, we present only the numerical study of simulating the thermo-mechanical behavior for an SMA enhanced lip seal, leaving the test setup and results in the experimental counterpart. A pseudo 3D SMA model, considering 1D SMA behavior in the major loading direction and elastic response in other directions, was used to capture the thermo-mechanical behavior of SMA wires. The model was then implemented into ABAQUS using the user-defined material subroutine to inherit most features of the commercial finite element package. Two-way shape memory effect was also considered since the SMA material exhibits strong two-way effects. An axisymmetric finite element model was constructed to simulate a seal mounting on a shaft and the sealing pressure was calculated for both the regular seal and the SMA enhanced seal. Finally, the result was qualitatively compared with the experimental observation. Content Type Journal Article Pages 1-9 DOI 10.1007/s11665-011-9893-4 Authors Rui Qiao, BD Medical Research & Development, 9450 South State Street, Sandy, UT 84070, USA Xiujie Gao, General Motors R&D, MC 480-106-256, 30500 Mound Rd, Warren, MI 48090, USA L. Catherine Brinson, Department of Mechanical Engineering, Northwestern University, Evanston, IL 60208, USA Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    In this article, the effect of aging on the microstructure and shape memory effect (SME) of a hot-rolled Ni 49 Ti 36 Hf 15 alloy is studied. The alloy was prepared by vacuum induction melting (VIM) and homogenized at 1000 °C for 2 h. The homogenized alloy was then undergone 45% hot rolling at 850 °C and aging at temperatures of 500 and 600 °C for 2 h. Optical microscopy (OM) and scanning electron microscopy (SEM) conducted on the hot-rolled samples revealed that hot rolling improves microstructure, deformation, and recoverable strains such that the alloy recovers 3.10 of 3.23 and 5.61 of 6.25 strain in the homogenized and hot-rolled state, respectively. Aging, however, adversely affects the formability and SME of the alloy, which stems from the embrittling effect of the newly formed precipitates during the aging process. Content Type Journal Article Pages 1-5 DOI 10.1007/s11665-011-9885-4 Authors Mahdi Moshref Javadi, School of Metallurgy and Materials Engineering, Iran University of Science and Technology, P.O. Box 16844, Tehran, Iran Majid Belbasi, School of Metallurgy and Materials Engineering, Iran University of Science and Technology, P.O. Box 16844, Tehran, Iran Mohammad T. Salehi, School of Metallurgy and Materials Engineering, Iran University of Science and Technology, P.O. Box 16844, Tehran, Iran M. Reza Afshar, Department of Materials Engineering, Science and Research Branch, Islamic Azad University, Tehran, 14778-93855, Iran Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    The uniaxial behavior of Nitinol in different forms and at different temperatures has been well documented in the literature. Mathematical models for the three-dimensional behavior of this class of materials, covering superelasticity, plasticity, and shape memory effects have been previously developed. Phenomenological models embedded in FEA analysis are part of common practice today in the development of devices made out of Nitinol. In vivo loading of medical devices has cyclic characteristics. There have been some indications in the literature that cyclic loading of Nitinol modifies substantially its behavior. A consortium of several stent manufacturers, Safe Technology and Dassault Systèmes Simulia Corp., dedicated to the development of fatigue laws suitable for life prediction of Nitinol devices, has conducted an extensive experimental study of the modifications in uniaxial behavior of both Nitinol wire and tubing due to cyclic loading. The Abaqus Nitinol material model has been extended to capture some of the phenomena observed and is described in this article. Namely, a preload beyond 6% strain alters the transformation plateaus; if the cyclic load amplitude is large enough, permanent deformations (residual martensite) are observed; the lower plateau increases; and the upper plateau changes. The modifications to the upper plateau are very interesting in the sense that it appears broken: its start stress gets lowered creating a new plateau up to the highest level of cyclic strain, followed by resuming the original plateau until full transformation. Since quite often the geometry of a device at the point at which it is subjected to cyclic loading is very much dependent on the manufacturing, deployment, and preloading sequence, it is important that analyses be conducted with the original material behavior up to that point, and then with the cyclic behavior thereafter. Content Type Journal Article Pages 1-8 DOI 10.1007/s11665-011-9883-6 Authors Nuno Rebelo, Dassault Systemes Simulia Corp. Western Region, Fremont, CA USA Achim Zipse, Bard Peripheral Vascular, Karlsruhe, Germany Martin Schlun, Bard Peripheral Vascular, Karlsruhe, Germany Gael Dreher, Bard Peripheral Vascular, Karlsruhe, Germany Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    Due to unique optical properties of high birefringent (Hi-Bi) fibers for sensing and coherent optical communications, there is a strong interest in process optimization at preform fabrication and fiber drawing stages. Boron-doped silica cladding acts as stress-applying part resulting in polarization properties of Hi-Bi fibers that are strongly dependent on chemical composition. Using modified chemical vapor deposition (MCVD) technique, B 2 O 3 -doped silica preform rods were synthesized under different precursor gas flow conditions. Qualitative information about B 2 O 3 -SiO 2 system composition was derived from etching behavior in nonbuffered HF solution and subsequent microstructural examination using scanning electron microscope. Significant degree of B 2 O 3 incorporation was seen in case of high BCl 3 :SiCl 4 ratio and mild oxygen-deficient processing conditions. Increasing the B 2 O 3 content to ~26 mol% led to a corresponding increase in coefficient of thermal expansion (CTE) to a maximum value of 2.35 ppm/K. The value of refractive index (RI), on the other hand, was found to decrease with increased B 2 O 3 incorporation. A qualitative correlation between B 2 O 3 and SiO 2 system composition and physical properties such as CTE and RI was established. Content Type Journal Article Pages 1-6 DOI 10.1007/s11665-011-9902-7 Authors Mohammad Islam, School of Chemical & Materials Engineering (SCME), National University of Sciences & Technology (NUST), Sector H-12, Islamabad, Pakistan Muhammad Rizwan Saleem, Department of Mathematics and Physics, University of Eastern Finland, Joensuu, Finland Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    In the present work, the influence of step annealing heat treatment on the microstructure and pitting corrosion resistance of super duplex stainless steel UNS S32760 welds have been investigated. The pitting corrosion resistance in chloride solution was evaluated by potentiostatic measurements. The results showed that step annealing treatments in the temperature ranging from 550 to 1000 °C resulted in a precipitation of sigma phase and Cr 2 N along the ferrite/austenite and ferrite/ferrite boundaries. At this temperature range, the metastable pits mainly nucleated around the precipitates formed in the grain boundary and ferrite phase. Above 1050 °C, the microstructure contains only austenite and ferrite phases. At this condition, the critical pitting temperature of samples successfully arrived to the highest value obtained in this study. Content Type Journal Article Pages 1-6 DOI 10.1007/s11665-011-9834-2 Authors M. Yousefieh, Department of Materials Engineering, Isfahan University of Technology, Isfahan, 84156-83111 Iran M. Shamanian, Department of Materials Engineering, Isfahan University of Technology, Isfahan, 84156-83111 Iran A. Saatchi, Department of Materials Engineering, Isfahan University of Technology, Isfahan, 84156-83111 Iran Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    Reconstruction of the digestive system lumen patency (anastomosis creation) after its partial surgical removal is a common and crucial procedure. The conventional anastomosis methods use devices for mechanical suturing which are associated with high failure risk and can lead to major complications. The compression anastomosis as a sutureless method seems to be a promising alternative. However, attempts during the last two centuries have not been completely successful due to the complex character of the tissue-healing process. The specific mechanical behavior of Nitinol alloys was applied to the force element of the compression devices. These devices are becoming more widely adopted in surgery practice. The compression anastomosis device enables the anastomosis of colonic and intestinal tissue based on compression forces exerted by Nitinol leaf springs. By means of changing the strain distribution in the stressed leaves with varying moments of inertia, one can gain full control of the different stages in the force-deflection profile (i.e., linear elastic stage and the force plateau stage). The target of this study is the comparison of different Nitinol leaf geometries and evaluation of the finite elements analysis as a tool for preliminary design of such geometries. The results of this analysis allow us to establish regulation of the spring’s mechanical behavior, thus controlling the anastomosis creation in the compression anastomosis device. Content Type Journal Article Pages 1-7 DOI 10.1007/s11665-011-9841-3 Authors Amir Weizman, NiTi Surgical Solutions, Yad Harutzim Street, See’im Industrial Park Building 9E, P.O. Box 8634, 42506 Netanya, Israel Leonid Monassevitch, NiTi Surgical Solutions, Yad Harutzim Street, See’im Industrial Park Building 9E, P.O. Box 8634, 42506 Netanya, Israel Kobby Greenberg, NiTi Surgical Solutions, Yad Harutzim Street, See’im Industrial Park Building 9E, P.O. Box 8634, 42506 Netanya, Israel Shahar Millis, NiTi Surgical Solutions, Yad Harutzim Street, See’im Industrial Park Building 9E, P.O. Box 8634, 42506 Netanya, Israel Boaz Harari, NiTi Surgical Solutions, Yad Harutzim Street, See’im Industrial Park Building 9E, P.O. Box 8634, 42506 Netanya, Israel Idan Dar, C.A.S. Ltd., 2 Etgar Street, 39032 Tirat Hacarmel, Israel Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    This study demonstrates the production of highly dense binary NiTi by spark plasma sintering (SPS) of elemental Ni and Ti powders. The sintered billets were extruded to 0.7 mm wire for tensile testing. Excellent mechanical properties and very dense microstructures were obtained in the wires produced in this way. The material demonstrated 4% recoverable strain, 14% elongation at fracture and 630 MPa ultimate tensile stress. Furthermore, a close control of the level of impurities was also possible. This highlights the efficacy of the SPS route in production-capacity manufacture of NiTi products. Content Type Journal Article Pages 1-5 DOI 10.1007/s11665-011-9837-z Authors J. Butler, Materials and Surface Science Institute, University of Limerick, Limerick, Ireland P. Tiernan, Materials and Surface Science Institute, University of Limerick, Limerick, Ireland A. A. Gandhi, Materials and Surface Science Institute, University of Limerick, Limerick, Ireland K. McNamara, Materials and Surface Science Institute, University of Limerick, Limerick, Ireland S. A. M. Tofail, Materials and Surface Science Institute, University of Limerick, Limerick, Ireland Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    Al 2 O 3 ceramic/stainless steel joints were fabricated by activated molybdenum-manganese (Mo-Mn) sintering metallization plus vacuum brazing using Ag-28 wt.% Cu alloy. The bonding mechanisms including metallization and interfacial bonding were analyzed and discussed by means of scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and x-ray diffraction (XRD). Tests were also carried out to examine the influence of brazing on joint shear strength. The metallization mechanisms of glassy phase migration and chemical reaction were confirmed experimentally, while Ni coating was found to play a key role in the joining of metallized ceramic to metal via the Ag-Cu filler layer. As a result of the joining, the average shear strength of the joints exceeds 95 MPa, with the maximum reaching 110 MPa. Content Type Journal Article Pages 1-6 DOI 10.1007/s11665-011-9840-4 Authors G. W. Liu, MOE Key Laboratory for Strength and Vibration, Xi’an Jiaotong University, Xi’an, 710049 China G. J. Qiao, State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an, 710049 China H. J. Wang, State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an, 710049 China J. P. Wang, State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an, 710049 China T. J. Lu, MOE Key Laboratory for Strength and Vibration, Xi’an Jiaotong University, Xi’an, 710049 China Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    MnFe 2 O 4 octahedra have been prepared by reaction of Mn 2+ ions and Fe 3+ in alkaline condition via heat treatment of the coprecipitation product. The as-prepared powders were characterized in detail by conventional techniques such as powder x-ray diffraction; field emission electron microscopy and transmission electron microscopy. Vibrating sample magnetometer was used to determine the magnetic properties at room temperature. The results show that the MnFe 2 O 4 octahedra were single crystals with cubic jacobsite structure and a size distribution from 0.8 to 1.0 μm. The octahedra obtained at 1100 and 1200 °C exhibited a ferromagnetic behavior with the coercive force ( H c ) value of 49.03 and 39.23 Oe, saturation magnetization ( M s ) value of 42.93 and 47.98 emu/g and remanent magnetization ( M r ) value of 2.16 and 2.55 emu/g, respectively. It is indicated that the heat treatment temperature has a significant effect on the formation of the jacobsite structure. Furthermore, a possible mechanism was also proposed to account for the growth of these products. Content Type Journal Article Pages 1-4 DOI 10.1007/s11665-010-9805-z Authors Hua Jiao, Department of Chemistry and Chemical Engineering, Weinan Teachers University, Wei Nan, 714000 China Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    Two representative soil models are compared and contrasted within two transient nonlinear dynamics computational analyses. The first soil model is representative of a discrete-particle group of models, while the other is a typical continuum-type consolidated-soil model. The two computational analyses involved: (a) the case of a soil slug impacting a rigid flat surface and (b) the case of detonation of a mine shallow buried in soil and the interaction of the resulting gaseous detonation products, mine fragments, and soil ejecta with a plate-like deformable steel target. The results obtained show that the use of the computationally more expensive particle mechanics-based soil models is fully justified only in the case of loose (low-density) soil. In addition, the magnitude of the particle-to-particle coefficient of restitution has been found to have a second-order effect on the extent of momentum transferred from the moving soil to the target and that it may be substantially different from its effective counterpart for the entire loose-soil agglomerate. Content Type Journal Article Pages 1-16 DOI 10.1007/s11665-011-9844-0 Authors M. Grujicic, Department of Mechanical Engineering, Clemson University, 241 Engineering Innovation Building, Clemson, SC 29634-0921, USA B. Pandurangan, Department of Mechanical Engineering, Clemson University, 241 Engineering Innovation Building, Clemson, SC 29634-0921, USA A. Hariharan, Department of Mechanical Engineering, Clemson University, 241 Engineering Innovation Building, Clemson, SC 29634-0921, USA Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    Current treatments for gait pathologies associated with neuromuscular disorders may employ a passive, rigid brace. While these provide certain benefits, they can also cause muscle atrophy. In this study, we examined NiTi shape memory alloy (SMA) wires that were annealed into springs to develop an active, soft orthotic (ASO) for the knee. Actively controlled SMA springs may provide variable assistances depending on factors such as when, during the gait cycle, the springs are activated; ongoing muscle activity level; and needs of the wearer. Unlike a passive brace, an active orthotic may provide individualized control, assisting the muscles so that they may be used more appropriately, and possibly leading to a re-education of the neuro-motor system and eventual independence from the orthotic system. A prototype was tested on a suspended, robotic leg to simulate the swing phase of a typical gait. The total deflection generated by the orthotic depended on the knee angle and the total number of actuators triggered, with a max deflection of 35°. While SMA wires have a high energy density, they require a significant amount of power. Furthermore, the loaded SMA spring response times were much longer than the natural frequency of an average gait for the power conditions tested. While the SMA wires are not appropriate for correction of gait pathologies as currently implemented, the ability to have a soft, actuated material could be appropriate for slower timescale applications. Content Type Journal Article Pages 1-5 DOI 10.1007/s11665-011-9858-7 Authors Leia Stirling, Wyss Institute, Harvard University, 5th Floor CLSB, 3 Blackfan Circle, Boston, MA 02115, USA Chih-Han Yu, Wyss Institute and the School of Engineering and Applied Sciences, Harvard University, 5th Floor CLSB, 3 Blackfan Circle, Boston, MA 02115, USA Jason Miller, Wyss Institute and the School of Engineering and Applied Sciences, Harvard University, 5th Floor CLSB, 3 Blackfan Circle, Boston, MA 02115, USA Elliot Hawkes, Wyss Institute and the School of Engineering and Applied Sciences, Harvard University, 5th Floor CLSB, 3 Blackfan Circle, Boston, MA 02115, USA Robert Wood, Wyss Institute and the School of Engineering and Applied Sciences, Harvard University, 4th Floor, 60 Oxford Street, Cambridge, MA 02138, USA Eugene Goldfield, Wyss Institute, Harvard University and Children’s Hospital Boston, 5th Floor CLSB, 3 Blackfan Circle, Boston, MA 02115, USA Radhika Nagpal, Wyss Institute and School of Engineering and Applied Sciences, Harvard University, 235 Maxwell Dworkin, 33 Oxford Street, Cambridge, MA 02138, USA Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    NiTi-based shape memory alloys (SMAs) exhibit an unusual stress distribution at the crack tip as compared to common engineering materials, due to a stress-induced martensitic transformation resulting from highly localized stresses. Understanding the fracture mechanics of NiTi-based SMAs is critical to many of their applications. Here, we develop an analytical model, which predicts the boundaries of the transformation region in the crack tip vicinity of NiTi-based SMAs. The proposed model is based on a recent analytical approach which uses modified linear elastic fracture mechanics concepts to predict the crack tip stress distribution and transformation region in SMAs but, unfortunately, it applies only to the plane stress condition. To overcome this limitation, the proposed model accounts for stress triaxiality, which plays an important role in restricting crack tip plastic deformations in common ductile metals as well as the stress-induced martensite in NiTi SMAs. The effects of triaxial stress at the crack tip are taken into account by including a new parameter, the transformation constraint factor, which is based on the plastic constraint factor of elasto-plastic materials. The predictions of the model are compared with synchrotron x-ray micro-diffraction observations and satisfactory agreement is observed between the two results. Finally, the evolution of crack tip transformation boundaries during fracture tests of miniature compact tension specimens is predicted and the effects of applied load and crack length are discussed. Content Type Journal Article Pages 1-8 DOI 10.1007/s11665-011-9852-0 Authors C. Maletta, University of Calabria—Mechanical Engineering, P. Bucci 44C, 87030 Arcavacata di Rende, CS Italy M. L. Young, Institut fur Werkstoffe, Ruhr-Universitat, Bochum, Germany Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    The mechanical behavior of superelastic springs is investigated in this study. The goal is to evaluate the device response and to exploit the material superelastic behavior, main concerns being material and geometrical response nonlinearity. The investigation is made of two parts, i.e., an experimental campaign and a numerical model proposal. Experimental tests have been performed on superelastic SMA coil springs considering load history in tension and compression for three different spring geometrical configurations. Tested specimens experience a maximum elongation larger than the original spring axis length. The response is not symmetric and under compression it is affected by buckling instability. Nevertheless, experimental results show a very good superelastic behavior with no damage and with negligible residual displacements. Numerical analyses have been performed to reproduce the experimental campaign results. A simple finite element model is proposed. Experimental and numerical result agreement is very good. The numerical model turns out to be a powerful design tool even for the very complex geometrical and material nonlinear conditions under investigation. Hence, it is proposed as a useful tool for spring design validation and response prediction. Content Type Journal Article Pages 1-6 DOI 10.1007/s11665-011-9831-5 Authors Gabriele Attanasi, Eucentre, European Centre for Training and Research in Earthquake Engineering, Pavia, Italy Ferdinando Auricchio, Dipartimento di Meccanica Strutturale, Università degli Studi di Pavia, Pavia, Italy Marco Urbano, Saes Getters, Lainate, Milano, Italy Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    Disability caused by nonunited fracture of the clavicle is a rare condition that is expressed by local pain. This condition is usually treated by reduction of the fracture and stable fixation with augmentation by autogenous bone graft. This is a retrospective study to assess outcome of the treatment of clavicular nonunion with a novel shape memory Ni-Ti alloy swan-like bone connector (SMC). August, 2003 to December, 2006, 5 consecutive patients with clavicular nonunion were treated using SMC in our hospital. The SMC device was cooled with ice before implantation and then warmed to 40-50 °C after implantation, to produce balanced axial and compression forces that would stabilize the fracture. We have used cancellous bone grafting in all our cases to obtain solid healing. Average follow-up was 37 months (range 25-58). In all patients, satisfactory osseous union was achieved. There was no complication from the hardware. The average Constant score which is for evaluating function of injured shoulder after operation was 86 points (average Constant score for the unaffected shoulder was 95). All patients were very satisfied with the treatment and outcome. The SMC provides a new effective method for fracture fixation and treatment of bone nonunion for clavicle. Content Type Journal Article Pages 1-5 DOI 10.1007/s11665-011-9863-x Authors Xin-wei Liu, Department of Orthopaedic Surgery, Changhai Hospital, Second Military Medical University, Shanghai, 200433 China Shuo-gui Xu, Department of Orthopaedic Surgery, Changhai Hospital, Second Military Medical University, Shanghai, 200433 China Pan-feng Wang, Department of Orthopaedic Surgery, Changhai Hospital, Second Military Medical University, Shanghai, 200433 China Chun-cai Zhang, Department of Orthopaedic Surgery, Changhai Hospital, Second Military Medical University, Shanghai, 200433 China Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    Al-0.3Sc-0.15Zr-TiB 2 composites with varying additions of Mg were cast through a novel processing technique using oil Quenched Investment Casting (QIC). Addition of Mg resulted in grain refinement of the composite. Al 3 (Sc, Zr) primary particles and TiB 2 are responsible for grain refinement in these composites. Presence of fine nanosized uniformly distributed precipitates of Al 3 (Sc, Zr) at the peak age condition together with TiB 2 particles increase the strength and ductility of the composites. The presence of Sc and Zr reduces the size of TiB 2 particles down to 10 nm. The optimum magnesium content in the composites studied lies between 3.5 and 6%. Content Type Journal Article Pages 1-8 DOI 10.1007/s11665-010-9829-4 Authors A. K. Lohar, CAMP, CMERI (CSIR), Durgapur, 713209 India B. N. Mondal, CAMP, CMERI (CSIR), Durgapur, 713209 India S. C. Panigrahi, Department of Metallurgy and Materials Engineering, IIT, Kharagpur, India Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    Investigations of composite based on a spray deposition Al-Zn-Mg-Cu alloy reinforced with SiC particles with the volume fraction of 15% and various extrusion ratios of 11-39 are presented. Bars with a diameter of 8-15 mm were obtained as the end product. Based on the microstructural examinations of the composite, we can find that SiC particles adhered mainly to the surface of the alloy droplets during deposition, leading to more SiC particles at the surface of the droplets and less in the inner. Thus, the distribution of SiC particles in the billet was characteristic of the layered feature. This layered feature of SiC particles was not completely removed by the following hot extrusion. The SiC particles were distributed like the streamline in the longitudinal direction. A higher extrusion ratio resulted in an more uniform distribution of SiC particles. Ambient tensile tests made it possible to demonstrate that the mechanical properties improve with the increasing of extrusion ratio. The ultimate tensile strength and elongation achieve 475 MPa and 16.5% at an extrusion ratio of 39. Content Type Journal Article Pages 1-6 DOI 10.1007/s11665-011-9859-6 Authors Y. P. Sun, Mechanical Engineering Department, Guangxi University of Technology, Liuzhou, 545006 P. R. China H. G. Yan, School of Materials Science and Engineering, Hunan University, Changsha, 410082 P. R. China B. Su, School of Materials Science and Engineering, Hunan University, Changsha, 410082 P. R. China L. Jin, Mechanical Engineering Department, Guangxi University of Technology, Liuzhou, 545006 P. R. China J. M. He, Mechanical Engineering Department, Guangxi University of Technology, Liuzhou, 545006 P. R. China Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    The galvanic corrosion behavior of carbon steel-stainless steel couples with various cathode/anode area ratios was investigated in S 2− -containing solutions, which were in equilibrium with air, by electrochemical measurements, immersion test, and surface characterization. It is found that the galvanic corrosion effect on carbon steel anode increases with the cathode/anode area ratios, and decreases with the increasing concentration of S 2− in the solution. A layer of sulfide film is formed on carbon steel surface, which protects it from corrosion. When the cathode/anode area ratio is 1:1, the potentiodynamic polarization curve measurement and the weight-loss determination give the identical measurement of the galvanic corrosion effect. With the increase of the cathode/anode area ratio, the electrochemical method may not be accurate to determine the galvanic effect. The anodic dissolution current density of carbon steel cannot be approximated simply with the galvanic current density. Content Type Journal Article Pages 1-7 DOI 10.1007/s11665-011-9839-x Authors C. F. Dong, Corrosion and Protection Center, University of Science and Technology Beijing, Beijing, 100083 China K. Xiao, Corrosion and Protection Center, University of Science and Technology Beijing, Beijing, 100083 China X. G. Li, Corrosion and Protection Center, University of Science and Technology Beijing, Beijing, 100083 China Y. F. Cheng, Department of Mechanical & Manufacturing Engineering, University of Calgary, Calgary, AB T2N 1N4, Canada Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    An investigation of the fatigue and fracture characterization of the high pressure die cast (HPDC) AM60B magnesium alloy at −40 °C temperature was conducted by means of the constant load amplitude fatigue test. The results demonstrated that low temperature had a significant influence on alloy’s fatigue life; the life increased at −40 °C temperature as compared to that at room temperature. The fracture surfaces of the tested specimens were observed under a scanning electron microscope (SEM) to further understand the fracture phenomenon at low temperature. Content Type Journal Article Pages 1-6 DOI 10.1007/s11665-011-9842-2 Authors Md. Nur Hossain, Department of Civil and Resource Engineering, Dalhousie University, 1360 Barrington Street, Halifax, NS B3J 1Z1, Canada Farid Taheri, Department of Civil and Resource Engineering, Dalhousie University, 1360 Barrington Street, Halifax, NS B3J 1Z1, Canada Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495