ALBERT

Description: In this work, porous Ni-625 superalloys were produced by use of a water soluble pore forming agent prior to sintering. Carbamide particles were used as the space-holder materials. After mixing and compaction, the space-holder particles were extracted using warm water leaching over a range of temperatures. The porous green parts were subsequently thermally debinding to remove the paraffin wax under a pure Argon atmosphere, and subsequently sintered at high vacuum. The effects of volume fraction of space-holder particles on density, porosity, and elastic modulus were investigated. Microstructures were captured using optical and scanning electron microscopy. Pore size was quantified using image analysis software integral to the scanning electron microscopy. In addition, compression tests were conducted on the sintered samples.

Description: The hot deformation behavior of solution and aging FGH96 superalloy were investigated in the deformation temperature range of 1000-1175 °C and strain rate range of 0.001-5.0/s on a Gleeble-1500 thermo-mechanical simulator. The results show that the true stress-strain curves are typical of the occurrence of dynamic recrystallization (DRX). The value of the activation energy and materials constants of A and n was obtained through the hyperbolic sine function between the peak stress and Zener-Hollomon parameter. Optical microscopy observations of the grains showed that Zener-Hollomon parameter affected the DRX grain size obviously. In addition, the constitutive equations and DRX kinetics model were also built. The processing maps with the strain of 0.3 and 0.6 were obtained on the basis of dynamic materials model. The results predicted that there existed instability regions at around 1050 °C when the strain rate exceeds 0.01/s.

Description: In this paper, the results of fatigue behavior on friction stir welded joints of aluminum alloy EN AW 6082-T6 are reported. In particular, the study presents the influence of the geometry of a welding tool on fatigue strengths and tensile strengths. The test joints were prepared as single side welded and double side welded by FSW. The welding was performed at various linear welding speeds (224, 560, and 900 mm/min) and one rotational speed of 710 rev./min using three different tool shapes. The results of macro examination and tensile test led to the selection of a single set of tool movement parameters at which the test joints for fatigue test were made. Samples were tested in two states of surface condition, i.e., “as-welded” and with mechanically removed marks left by rotating and moving tool during FSW process. Studies have shown that fatigue behavior of FSW joints depends on the tool shape used in the welding process as well as the surface condition of welded joints and manner of joint production.

Description: Porous Fe-Al intermetallics with different nominal compositions (from Fe-8 wt.% Al to Fe-50 wt.% Al) were fabricated by Fe and Al elemental powders through reaction synthesis. The effects of the Al content on the pore structure properties, and the comparison of pore structure stabilities at high-temperatures among the porous Fe-Al intermetallics and porous Ti, Ni, 316L stainless steel samples, were systematically studied. Results showed that the open porosity, maximum pore size, and permeability vary with the Al content. Porous Fe-(25-30 wt.%) Al intermetallics show good shape controllability and excellent pore structure stability at 1073 K in air, which suggests that these porous Fe-Al intermetallics could be used for filtration at high temperatures.

Description: VO 2 thin films were deposited on soda lime glass substrates with ZnO, TiO 2 , SnO 2 , and CeO 2 thin films applied as buffer layers between the VO 2 films and the substrates in order to investigate the effect of buffer layer on the formation and the thermochromic properties of VO 2 film. Buffer layers with thicknesses over 50 nm were found to affect the formation of VO 2 film, which was confirmed by XRD spectra. By using ZnO, TiO 2 , and SnO 2 buffer layers, monoclinic VO 2 (VO 2 (M)) film was successfully fabricated on soda lime glass at 370 °C. On the contrary, films of VO 2 (B), which is known to have no phase transition near room temperature, were formed rather than VO 2 (M) when the film was deposited on CeO 2 buffer layer at the same film deposition temperature. The excellent thermochromic properties of the films deposited on ZnO, TiO 2 , and SnO 2 buffer layers were confirmed from the temperature dependence of electrical resistivity from room temperature to 80 °C. Especially, due to the tendency of ZnO thin film to grow with a high degree of preferred orientation on soda lime glass at low temperature, the VO 2 film deposited on ZnO buffer layer exhibits the best thermochromic properties compared to those on other buffer layer materials used in this study. These results suggest that deposition of VO 2 films on soda lime glass at low temperature with excellent thermochromic properties can be achieved by considering the buffer layer material having structural similarity with VO 2 . Moreover, the degree of crystallization of buffer layer is also related with that of VO 2 film, and thus ZnO can be one of the most effective buffer layer materials.

Description: Fe-Cr 3 C 2 hard coatings with varying Cr 3 C 2 content were produced on 35CrMo steel substrates by laser cladding. The experimental results showed that the coatings were uniform, continuous, and free of cracks. High adhesions between all produced coatings and their corresponding substrates were obtained due to the metallurgical interfaces between them. The microstructures of the coatings were mainly composed of austenitic dendrites and M 7 C 3 . The microhardness gradually increased from the bottom to the top of the coating, and increased with elevation of Cr 3 C 2 content. The Fe-Cr 3 C 2 coatings improved the sliding wear resistance of the 35CrMo steel substrates obviously, and the dominant wear mechanism was spalling fatigue, with plowed grooves on the worn surfaces.

Description: PVA-TiO 2 nanocomposite polymer electrolytes (PEs) were produced with different amounts of TiO 2 (0, 5, 10, 15, and 20 wt.%) using the electrospinning process. Morphological studies of PVA-TiO 2 nanofibers were accomplished with SEM. PVA-TiO 2 membranes exhibited a high porosity of 79-91%. The impedance results showed that incorporation of TiO 2 into the nanofiber membrane improved its ionic conductivity from 0.7 × 10 −5 to 2.5 × 10 −5  S/cm at room temperature. Nanofiber PEs showed very good reversibility and electrochemical stability up to 4.7 V. Diffusion coefficient of Li ion into PVA-TiO 2 nanocomposite PEs was estimated by using a complex numerical model of partial differential equation for evaluation of ion transmission. Diffusion coefficient of PVA-TiO 2 PEs containing different amounts of TiO 2 (0, 5, 10, 15, and 20 wt.%) increased with increasing the nanoparticles content.

Description: Synthesis of nanostructure titania powders and in situ crystallization of anatase coating layer on sintered alumina granules by solvothermal method were investigated. In coating process, addition of polyvinyl alcohol (PVA) as binder to solvothermal solution was also studied. Microstructure analyses of powders showed that crystallization and growth of nanostructure anatase phase in a thin gel layer were enhanced with temperature increase. The titania nanopowders synthesized at 120 °C and 8 h represented photodegradation of methyl orange solution as model wastewater up to maximum 94% yield in slurry photoreactor. However, in coating process, with increasing temperature to 220 °C and coating time to 24 h, adhesion and photocatalytic properties of the coated layer were improved. Furthermore, PVA binder addition led to formation of more uniform layer with less attrition loss in the reactor.

Description: Microstructure evolution after solutionizing and ageing treatment of cast AZ80 Mg alloy were investigated using optical and scanning electron microscopy. Effect of these treatments on grain size, β-Mg 17 Al 12 intermetallic phase, mechanical behavior, and flow asymmetry were investigated. The initial continuous network of β-phase found to be reduced after solutionizing. The dissolution of β-phase and simultaneous grain growth are found to be interrelated. Mechanical properties including yield strength, maximum strength (ultimate compressive strength), and maximum strain attainable in compressive found almost twice than the corresponding values obtained in tension. The asymmetry in compressive and tensile properties is found to decrease with grain size at certain solutionizing duration. Particular heat treatment found to offer best combination of tensile compressive flow properties in AZ80 Mg alloy. Aging under certain conditions found to minimize the strength asymmetry.

Description: In the present study, A-TIG welding was carried out on grade 91 steel plates of size 220 × 110 × 10 mm using the in-house developed activated flux to produce butt-joints. The room-temperature impact toughness of the A-TIG as-welded joint was low due to the presence of untempered martensite matrix despite the low microinclusion density caused by activated flux and also low δ-ferrite (〈0.5 %) content. Toughness after postweld heat treatment (PWHT) at 760 °C-2 h was 20 J as against the required value of 47 J as per the specification EN: 1557:1997. However, there was a significant improvement in impact toughness after PWHT at 760 °C for 3 h. The improvement in toughness was attributed to softening of martensite matrix caused by precipitation of carbides due to tempering reactions. The precipitates are of type M 23 C 6 , and they are observed at grain boundary as well as within the grains. The A-TIG-processed grade 91 steel weld joint was found to meet the toughness requirements after PWHT at 760 °C-3 h. Observations of fracture surfaces using SEM revealed that the as-welded joint failed by brittle fracture, whereas post-weld heat-treated weld joints failed by decohesive rupture mode.

Description: Cu-7Cr-0.07Ag alloys were prepared by casting and directional solidification, from which deformation-processed in situ composites were prepared by thermo-mechanical processing. The microstructure, mechanical properties, and electrical properties were investigated using optical microscopy, scanning electronic microscopy, tensile testing, and a micro-ohmmeter. The second-phase Cr grains of the directional solidification Cu-7Cr-0.07Ag in situ composite were parallel to the drawing direction and were finer, which led to a higher tensile strength and a better combination of properties.

Description: In this paper, two different heat treatment processes of a 9% Ni steel for large liquefied natural gas storage tanks were performed in an industrial heating furnace. The former was a special heat treatment process consisting of quenching and intercritical quenching and tempering (Q-IQ-T). The latter was a heat treatment process only consisting of quenching and tempering. Mechanical properties were measured by tensile testing and charpy impact testing, and the microstructure was analyzed by optical microscopy, transmission electron microscopy, and x-ray diffraction. The results showed that outstanding mechanical properties were obtained from the Q-IQ-T process in comparison with the Q-T process, and a cryogenic toughness with charpy impact energy value of 201 J was achieved at 77 K. Microstructure analysis revealed that samples of the Q-IQ-T process had about 9.8% of austenite in needle-like martensite, while samples of the Q-T process only had about 0.9% of austenite retained in tempered martensite.

Description: Stress corrosion cracking studies of aluminum alloys AA2219, AA8090, and AA5456 in heat-treated and non heat-treated condition were carried out using electrochemical noise technique with various applied stresses. Electrochemical noise time series data (corrosion potential vs. time) was obtained for the stressed tensile specimens in 3.5% NaCl aqueous solution at room temperature (27 °C). The values of drop in corrosion potential, total corrosion potential, mean corrosion potential, and hydrogen overpotential were evaluated from corrosion potential versus time series data. The electrochemical noise time series data was further analyzed with rescaled range ( R / S ) analysis proposed by Hurst to obtain the Hurst exponent. According to the results, higher values of the Hurst exponents with increased applied stresses showed more susceptibility to stress corrosion cracking as confirmed in case of alloy AA 2219 and AA8090.

Description: Ti 5 Si 3 was fabricated by self-propagating high-temperature synthesis (SHS), mechanical-activated SHS (MASHS), and mechanical alloying with the aim of investigating the effect of milling energy on final product. For MASHS process, Ti and Si as starting materials were milled by high energy ball milling, with ball-to-powder weight ratio (BPR) of 10:1, for different times (1, 3, and 6 h), then pressed to form pellets. Green compacts were placed in a tube furnace preheated to three different temperatures of 1000, 900, and 800 °C with argon atmosphere for the synthesis. The milled and synthesized powders were characterized by means of XRD and SEM. The results showed that Ti 5 Si 3 was not formed during milling up to 3 h, after that a trace of Ti 5 Si 3 peaks can be detected from XRD pattern. The increase in milling time prior the combustion reaction caused a decrease in the crystallite size of the final product and ignition temperature of the reactant. The average crystallite sizes of Ti 5 Si 3 after activation of 1, 3, and 6 h were calculated 87, 55, and 48 nm, respectively. Higher milling energy in BPR 15:1, led to the full reaction and formation of nanostructured Ti 5 Si 3 in milling media by mechanical alloying method, even after 1 h. The crystallite sizes of Ti 5 Si 3 after milling of powders from 1, 3, and 6 h, were calculated 70, 26, and 14 nm, respectively. For the SHS process Ti and Si were mixed in the methanol. The combustion reactions were carried out in the tubular furnace and reactor. SEM results showed that Products were formed via MASHS process have more uniformity of microstructure compared to those synthesized via SHS process.

Description: In this paper, we present results of electrode durability testing and electrode design in a pulsed electrohydraulic discharge environment. Pulsed electrohydraulic forming (EHF) is an electrodynamic process based upon high-voltage discharge of capacitors between two electrodes positioned in a fluid-filled chamber. EHF enables a more uniform distribution of strains, widens the formability window, and reduces elastic springback in the final part when compared to traditional sheet metal stamping. This extended formability allows the fabrication of panels of alternative high strength alloys that are otherwise difficult to make conventionally. It was found that, of the materials tested, steel electrodes not only survived the stresses encountered in the EHF chamber but also had lower erosion rates compared to molybdenum. Erosion rates were found to be constant for low carbon steel at 3.7 mm 3 /discharge, and they were high enough that the initial tip geometry was rapidly worn away and a more geometrically and thus electrically stable tip geometry had to be selected. Entrained air in the system had little influence on erosion rates but numerical modeling suggests that the erosion process takes place during the very initial stages of the pulse. Lastly, it was determined that the electrodes discussed in this paper can survive 2000 pulses.

Description: With the aim to produce a coating having good corrosion and wear resistance alongside hardness but lesser friction coefficient, Ni-P-PTFE-Al 2 O 3 (NiPPA) dispersion coating was developed. This was achieved by introducing nanosized polytetrafluoroethylene (PTFE) and alumina (Al 2 O 3 ) in the Ni-P matrix deposited on mild steel substrate. The coating was characterized using scanning electron microscopy, energy dispersive analysis of x-ray, and x-ray diffractrometry. Microhardness and wear resistance of the coating was measured using Vicker’s hardness tester and Pin-on-Disc method, respectively. The corrosion behavior was measured using electrochemical polarization and immersion tests with and without exposure in 3.5% NaCl solution. It is observed that codeposition of Al 2 O 3 and PTFE particles with Ni-P coating results in comparatively smooth surface with nodular grains. The NiPPA coating was observed to have moderate hardness between electroless Ni-P-PTFE and Ni-P-Al 2 O 3 coating and good wear resistance with lubricating effect. Addition of both PTFE and Al 2 O 3 is observed to enhance corrosion resistance of the Ni-P coating. However, improvement in corrosion resistance is more due to addition of Al 2 O 3 than PTFE. Continuous exposure for 10-20 days in corrosive solution is found to deteriorate corrosion protection properties of the coating.

Description: A dimensional deformation measurement system (XJTUDIC/VS) based on digital image correlation was employed to measure the deformation and strain field of Cu/Al clad metals made using the explosive welding technique. An extensometer with a gage length of 50 mm was used during the Q235 tensile test to verify the strain measurement accuracy of the system. The results demonstrate that the accuracy of the XJTUDIC/VS system is ≥0.5%, which is very close to that of the extensometer. The anisotropy of Cu/Al clad metals under uniaxial tension after 0, 1.5, 2.5, and 4.5% prestrain was investigated. With an increase in strain, the true stress-strain curve varied at different directions in the same prestrains. The strain hardening rate, r value (changes from 0.1 to 0.9), and n value (changes from 0.25 to 0.35) all strongly depended on loading directions and prestrains. The linear relations between longitudinal strain and transverse strain were also influenced by tensile directions and prestrains. Cu/Al clad metals generally presented strong anisotropy.

Description: High cycle fatigue tests of a cast Al-12Si-CuNiMg alloy are carried out under different stress amplitudes at room temperature. The scanning and transmission electron microscopy observations are used to examine the fracture surfaces and dislocation structures of the tested material, respectively. The results show that the fatigue damage originates from the microstructural defects, and the fracture surface morphology is typical quasi-cleavage fracture. With the increasing strain amplitude, the material fatigue life obviously decreases; however, the dislocation density increases significantly, which leads to the formation of the dislocation walls and cells. Under the cycle loading, the eutectic Si phase and the secondary particles undergo fracture. The pinning effect of the precipitates on the dislocations becomes obvious, indicating that the Al-12Si-CuNiMg alloy has the cyclic hardening characteristic.

Description: The current study aimed to investigate the effect of fluidized sand bed (FB) quenching on the mechanical performance of B319.2 aluminum cast alloys. Traditional water and conventional hot air (CF) quenching media were used to establish a relevant comparison with FB quenching. Quality charts were generated using two models of quality indices to support the selection of material conditions on the basis of the proposed quality indices. The use of an FB for the direct quenching-aging treatment of B319.2 casting alloys yields greater UTS and YS values compared to conventional furnace quenched alloys. The strength values of T6 tempered B319 alloys are greater when quenched in water compared with those quenched in an FB or CF. For the same aging conditions (170°C/4h), the fluidized bed quenched-aged 319 alloys show nearly the same or better strength values than those quenched in water and then aged in a CF or an FB. Based on the quality charts developed for alloys subjected to different quenching media, higher quality index values are obtained by conventional furnace quenched-aged T6-tempered B319 alloys. The modification factor has the most significant effect on the quality results of the alloys investigated, for all heat treatment cycles, as compared to other metallurgical parameters. The results of alloys subjected to multi-temperature aging cycles reveal that the optimum strength properties of B319.2 alloys, however, is obtained by applying multi-temperature aging cycles such as, for example, 240 °C/2 h followed by 170 °C/8 h, rather than T6 aging treatments. The regression models indicate that the mean quality values of B319 alloys are highly quench sensitive due to the formation of a larger percent of clusters in Al-Si-Cu-Mg alloys. These clusters act as heterogeneous nucleation sites for precipitation and enhance the aging process.

Description: The effects of Ti addition on phase transformation, precipitation behavior, and microhardness response of Cu40Zn brass were investigated at elevated heat treatment (HT) temperatures using the powder metallurgy method. The volume fraction of the α phase increased with the elevated temperatures, which showed an equal value as that of the β phase at 400 °C, and reached a maximum value of 55.9% at 500 °C. The solid solubility of Ti in Cu40Zn brass matrix decreased as the HT temperature increased. Supersaturated Ti showed high chemical potential for precipitates' reaction in Cu40Zn brass. Lower HT temperature retained higher Ti solid solubility and fine precipitates. The precipitates presented in form of Cu 2 TiZn intermetallic compound, distributing uniformly in brass matrix which suppressed the phase and grain growth. After HT at elevated temperature, the precipitates coalesced, grew coarser, and segregated at the primary particle boundaries. The microhardness of the BS40-1.0Ti compact was primarily not only dependent on the solid solubility of Ti, but also dependent on the phase volume fraction of the α and β phases.

Description: Nihard Grade-4, a nickel-bearing cast iron widely used in slurry pumps and hydrodynamic components, is evaluated for its erosive wear response under mining conditions using a statistical approach. Experiments were conducted by varying the factors namely velocity, slurry concentration, angle of impingement, and pH in three levels, using L9 orthogonal array. Analysis of variance was used to rank the factors influencing erosive wear. The results indicate that velocity is the most influencing factor followed by the angle of impingement, slurry concentration, and pH. Interaction effects of velocity, slurry concentration, angle of impingement, and pH on erosion rate have been discussed. Wear morphology was also studied using SEM characterization technique. At lower angle (30°) of impingement, the erosion of material is by micro fracture and shallow ploughing with the plastic deformation of the ductile austenitic matrix. At the normal angle (90°) of impingement, the material loss from the surface is found because of deep indentation, forming protruded lips which are removed by means of repeated impact of the erodent.

Description: MAR-M247 is a nickel-based superalloy that contains 3 wt.% Ta (weight percent of tantalum). Considering the chemical similarity between tantalum and niobium (Nb) and the lower cost of Nb, a modified MAR-M247 superalloy was produced with total replacement of Ta by Nb in this work. The samples were previously solutioned at 1260°C for 8 h and then aged at different times (between 5 and 80 h) and temperatures (between 780 and 980°C). The microstructures of the aged samples were characterized with a scanning electron microscope (SEM and FEG-SEM, both with EDS). Simulations of the MC carbide and γ′ fraction and the Ta and Nb content in both MC carbide and γ′ phase were performed with Thermo-Calc software (TT_Ni8 database) and simulations of the γ′ growth rate and γ′ mean diameter were performed with JMatPro software. MC carbide with high Hf content was observed in all the aged samples, in agreement with thermodynamic simulation results. The equilibrium γ′ fraction decreases from 67 mol.% at 780°C to 52 mol.% at 980°C. Good agreement between the calculated and experimentally determined γ′ particle size was also found. The growth rate of γ′ at 980°C is about 8 times higher than that at 780°C and 3 times higher than that at 880°C. The hardness values do not change considerably after aging at 780 and 880°C. However, these values decrease significantly after aging at 980°C.

Description: Bulk texture measurement of multi-axial forged body center cubic interstitial free steel performed in this study using x-ray and neutron diffraction indicated the presence of a strong {101}〈111〉 single texture component. Viscoplastic self-consistent simulations could successfully predict the formation of this texture component by incorporating the complicated strain path followed during this process and assuming the activity of {101}〈111〉 slip system. In addition, a first-order estimate of mechanical properties in terms of highly anisotropic yield locus and Lankford parameter was also obtained from the simulations.

Description: The inhibition effect of cefoperazone (CP) on the corrosion behavior of carbon steel in 0.5 M HCl solution was studied using potentiodynamic polarization, electrochemical impedance spectroscopy, and electrochemical frequency modulation techniques along with scanning electron microscopy (SEM). Results showed that the inhibition efficiency increases with increasing inhibitor concentration and decreases with increasing the temperature. The results indicated that the inhibitive action of CP can be attributed to its adsorption. The results show that CP possesses excellent inhibiting effect for the corrosion of carbon steel and the inhibitor acts as mixed-type inhibitor. The adsorption process is spontaneous and follows Langmuir adsorption isotherm model. The surface adsorption of the inhibitor molecules decreases the double-layer capacitance and increases the polarization resistance. SEM results indicate the formation of an adsorbed protective film on the metal surface. The results obtained from the different techniques were in good agreement which prove the validity of these tools in the measurements of the tested inhibitor.

Description: Formability of magnesium alloys at room temperature or slightly elevated temperatures is low, and exhibiting poor resistance to strain localization and failure. However, it is possible to improve the formability of AZ31 magnesium alloy sheet at high strain rate such as by electromagnetic forming (or magnetic pulse forming). In this study, experimental investigation of uniaxial tension of AZ31 sheet by magnetic pulse forming at room temperature was presented. The approximate rectangular flat spiral coil was employed to carry out the experiments. The specimens used in the tension test by magnetic pulse forming were same as the quasi-static uniaxial test. The samples were placed close to the outside of coil where an approximately homogenous magnetic field distribution prevailed. The experimental results indicate that the total elongation of AZ31 sheet improves about 37% compared with the quasi-static case. Non-uniform deformation occurs in the specimen. The maximum strain takes place on the area C , where is plotted on the specimen. The major and minor principal strains at most increase by approximately 112 and 96% under 5.12 kJ energy. The experimental results obtained in this study provide the fundamentals for the investigation of high speed forming of AZ31 magnesium alloy sheets.

Description: ZrO 2 was brazed to Ti-6Al-4V using a Zr 55 Cu 30 Al 10 Ni 5 (at.%) amorphous filler in a high vacuum at 1173-1273 K. The influences of brazing temperature, holding time, and cooling rate on the microstructure and shear strength of the joints were investigated. The interfacial microstructures can be characterized as ZrO 2 /ZrO 2− x  + TiO/(Zr,Ti) 2 (Cu,Ni)/(Zr,Ti) 2 (Cu,Ni,Al)/acicular Widmanstäten structure/Ti-6Al-4V. With the increase in the brazing temperature, both the thickness of the ZrO 2− x  + TiO layer and the content of the (Zr,Ti) 2 (Cu,Ni) phase decreased. However, the acicular Widmanstäten structure gradually increased. With the increase in the holding time, the (Zr,Ti) 2 (Cu,Ni) phase decreased, and the thickness of the (Zr,Ti) 2 (Cu,Ni) + (Zr,Ti) 2 (Cu,Ni,Al) layer decreased. In addition, cracks formed adjacent to the ZrO 2 side under rapid cooling. The microstructures produced under various fabrication parameters directly influence the shear strength of the joints. When ZrO 2 and Ti-6Al-4V couples were brazed at 1173 K for 10 min and then cooled at a rate of 5 K/min, the maximum shear strength of 95 MPa was obtained.

Description: Mechanical alloying (MA) and the field-activated and pressure-assisted in situ synthesis (FAPAS) were combined to prepare the ultra-hard and super-abrasive AlMgB 14 with the characteristics of fast heating-up, high efficiency, and low energy cost. Such preparations using the elemental constituents, such as Al, Mg, and B, were performed at a vacuum annealed temperature of 1500 °C under a pressure of 60 MPa. The resultant ceramics were characterized by SEM, EDS, and XRD. It was shown that the samples contained uniform AlMgB 14 , and the maximum hardness on the sample surface may reach 32.5 GPa. Furthermore, a second experiment was performed, in which MgH 2 was used as one of the starting materials instead of elemental Mg, but this approach did not produce AlMgB 14 .

Description: The influences of Y and Y-rich mischmetal (Ym) additions on microstructural and compressive properties of as-cast Al-13Mg-0.8Mn alloy prepared by vacuum suction casting were investigated in this study. The average secondary dendrite arm spacing (SDAS) was decreased when adding Y and Ym additions. Moreover, the Al 2 Y and Al 2 Ym phases formed during the solidification were mainly distributed along the grain boundary. The mechanical results reveal that both Y and Ym additions are effective in increasing the compressive strength and hardness. The values of yield compressive strength, ultimate compressive strength, and Brinell hardness of the as-cast Al-13Mg-0.8Mn-0.8Y alloy are 357 MPa, 510 MPa, and 138, respectively. The improved mechanical properties are mainly attributed to fine SDAS and precipitation strengthening. A typical cleavage fracture mode is observed on the compressive fracture surfaces of the alloys.

Description: Finding the geometry and properties of a ceramic tile after its firing using simulations, is relevant because several defects can occur and the tile can be rejected if the conditions of the firing are inadequate for the geometry and materials of the tile. Previous works present limitations because they do not use a model characteristic of ceramics at high temperatures and they oversimplify the simulations. As a response to such shortcomings, this article presents a simulation with a three-dimensional Norton’s model, which is characteristic of ceramics at high temperatures. The results of our simulated experiments show advantages with respect to the identification of the mechanisms that contribute to the final shape of the body. Our work is able to divide the history of temperatures in stages where the evolution of the thermal, elastic, and creep deformations is simplified and meaningful. That is achieved because our work found that curvature is the most descriptive parameter of the simulation. Future work is to be realized in the creation of a model that takes into account that the shrinkage is dependent on the history of temperatures.

Description: Microstructure, mechanical properties, and wear resistance of B-bearing high-speed steel (HSS) roll material containing 0.90-1.00% C, 1.3-1.5% B, 0.8-1.5% W, 0.8-1.5% Mo, 4.6-5.0% Cr, 1.0-1.2% V, and 0.15-0.20% Ti were studied by means of the optical microscopy (OM), the scanning electron microscopy (SEM), x-ray diffraction (XRD), hardness, impact toughness, and pin-on-disk abrasion tests. The results showed that as-cast structure of B-bearing HSS consisted of α-Fe-, M 23 (B,C) 6 -, M 3 (B 0.7 C 0.3 )-, and M 2 (B,C)-type borocarbides, a small quantity of retained austenite, and a small amount of TiC. The hardness and impact toughness values of as-cast B-bearing HSS reached 65-67 HRC and 80-85 kJ/cm 2 , respectively. There were many M 23 (B,C) 6 -precipitated phases in the matrix after tempering, and then, with increasing temperature, the amount of precipitated phases increased considerably. Hardness of B-bearing HSS gradually decreased with the increasing tempering temperature, and the change of tempering temperature had no obvious effect on impact toughness. B-bearing HSS tempered at 500 °C has excellent wear resistance, which can be attributed to the effect of boron.

Description: The objective of this work is to model the thermal expansion coefficients of various Ni-based superalloys used in gas turbine components. The thermal expansion coefficient is described as a function of temperature, chemical composition including Ni, Cr, Co, Mo, W, Ta, Nb, Al, Ti, B, Zr, and C contents as well as heat treatment including solutionizing and aging. Experimental values are well described and their relative changes well correlated by the model. Because gas turbine engine components operate under severe loading conditions and at high and varying temperatures, the prediction of their thermal expansion coefficient is crucial. The model developed in this work can be useful for design optimizations for minimizing thermo-mechanical stresses between the base alloys and potential protective coatings or adjacent components. It can substantially contribute to improve the performance and service life of gas turbine components.

Description: An investigation was carried out to examine the influence of structural and mechanical properties on wear behavior of austempered ductile iron (ADI). Ductile iron (DI) samples were austenitized at 900 °C for 60 min and subsequently austempered for 60 min at three temperatures: 270, 330, and 380 °C. Microstructures of the as-cast DI and ADIs were characterized using optical and scanning microscopy, respectively. The structural parameters, volume fraction of austenite, carbon content of austenite, and ferrite particle size were determined using x-ray diffraction technique. Mechanical properties including Vicker’s hardness, 0.2% proof strength, ultimate tensile strength, ductility, and strain hardening coefficient were determined. Wear tests were carried out under dry sliding conditions using pin-on-disk machine with a linear speed of 2.4 m/s. Normal load and sliding distance were 45 N and 1.7 × 10 4  m, respectively. ADI developed at higher austempering temperature has large amounts of austenite, which contribute toward improvement in the wear resistance through stress-induced martensitic transformation, and strain hardening of austenite. Wear rate was found to depend on 0.2% proof strength, ductility, austenite content, and its carbon content. Study of worn surfaces and nature of wear debris revealed that the fine ausferrite structure in ADIs undergoes oxidational wear, but the coarse ausferrite structure undergoes adhesion, delamination, and mild abrasion too.

Description: This paper proposes a new level of understanding of two-point incremental forming (TPIF) with partial die by means of a combined theoretical and experimental investigation. The theoretical developments include an innovative extension of the analytical model for rotational symmetric single point incremental forming (SPIF), originally developed by the authors, to address the influence of the major operating parameters of TPIF and to successfully explain the differences in formability between SPIF and TPIF. The experimental work comprised the mechanical characterization of the material and the determination of its formability limits at necking and fracture by means of circle grid analysis and benchmark incremental sheet forming tests. Results show the adequacy of the proposed analytical model to handle the deformation mechanics of SPIF and TPIF with partial die and demonstrate that neck formation is suppressed in TPIF, so that traditional forming limit curves are inapplicable to describe failure and must be replaced by fracture forming limits derived from ductile damage mechanics. The overall geometric accuracy of sheet metal parts produced by TPIF with partial die is found to be better than that of parts fabricated by SPIF due to smaller elastic recovery upon unloading.

Description: The long-term durability of ceramics coated glass with high performance should be appropriately evaluated prior to their applications. Fatigue properties of such materials should be clarified to ensure the long-term durability. In this work, a borosilicate glass was coated with single- and two-layered ceramic thin films by a sputtering method. Fatigue tests of coated glass were conducted under bending mode, and fatigue properties of coated glass were investigated. It was revealed that the fatigue life of glass coated with two-layered film became longer compared with those of glass substrate and glass coated single-layered film. Hardness as surface characteristics of coated films, and bending strength as bulk property of coated glass were correlated with the average fatigue life, though no good correlation was found between them. Fatigue resistance strength was proposed as another strength parameter. It was found that the average fatigue life was adequately expressed by a power function of fatigue resistance strength.

Description: In this paper, the influence of the cooling rate and cooling media after a standard solution heat treatment on the size and distribution of the gamma prime phase (γ′) in the nickel-based super alloy INCONEL 738 in over-aged conditions is described. The volume fraction of the gamma prime depends on the chemical composition of the alloy, the solution treatment temperature and the cooling rate; in over-aged alloys (i.e., with more than 25,000 h of service) the volume fraction of γ′ is about 78.8%. However, it has been demonstrated that in order to maintain excellent creep strength a volume fraction of at least 60% or lower is required. In this work the volume fraction was optimized between 40 and 55% by means of a standard solution heat treatment at 1120 °C using different cooling gases. A γ′ volume fraction of 54.8% was obtained by using argon as the cooling medium at a cooling rate of 87 °C/min, producing a precipitate of partial distribution of primary and secondary γ′. Better results were obtained in a nitrogen atmosphere at a cooling rate of 287 °C/min, leading to a volume fraction of 40% and obtaining a total re-precipitation of primary and secondary γ′.

Description: In this study, we have characterized the microstructure, resistivity, and dynamic deformation behavior of Cu/Ru/SiO 2 and Cu/SiO 2 samples under scratch loading conditions. Cu/Ru/SiO 2 samples showed higher elastic recovery and hardness when compared to the Cu/SiO 2 samples. In the case of Cu/Ru/SiO 2 samples, Ru acts as a glue layer between the Cu and the SiO 2 substrate providing both strength and toughness against dynamic loading. Hence, the critical load for delamination is higher for Cu/Ru/SiO 2 samples compared to Cu/SiO 2 samples. Our results show that Cu/Ru/SiO 2 thin films present significant potential to be used in Cu metallization.

Description: The inhibition effect of mild steel (MS) corrosion in 1 M HCl was studied by the addition of indole alkaloids (crude) isolated from Alstonia angustifolia var. latifolia ( A. latifolia ) leaves at 303 K. Potentiodynamic polarization, impedance spectroscopy, scanning electron microscopy (SEM), and Fourier transform infrared (FTIR) analyses were used for this study. Results show that the isolated alkaloid extract of A. latifolia is a good inhibitor and exhibited maximum inhibition efficiency (above 80%) at concentrations between 3 and 5 mg/L. Polarization measurements indicated that the inhibitor does not alter the mechanism of either anodic or cathodic reactions and acted as mixed-type inhibitor. The inhibition efficiencies of both electrochemical techniques are found to be in good agreement and adsorption of inhibitor follows Langmuir isotherm. Adsorption of inhibitor over metal surface was well supported by the SEM studies, while FTIR studies evidenced the presence of indole alkaloids as green inhibitor that reduces the rate of corrosion.

Description: The coating formation in a kinetic spray process mainly depends on the impact of inflight particles at a high velocity. The plastic deformation at the impact interface would disrupt the native oxide scale on the particle and the substrate to generate the intimate contact of the atomic structures. Accordingly, it poses a challenge in producing ceramic coating during kinetic spray because of the lack of plasticity of ceramic powders at room temperature. In this study, we proposed to prepare ZrO 2 ceramic coatings using partially amorphized powder with nanometer size in the kinetic spray process. To prepare the powder for the use of the kinetic spray, the amorphization and grain refinement of ZrO 2 powder in mechanical ball milling were studied. The results showed that the amorphization and grain refinement were improved because of the formation of solid solution when the CeO 2 agent was added. Subsequently, a nearly spherical powder was achieved via spray drying using the milled powders. The plasticity of the milled powders was tested in the kinetic spray process using Nitrogen as process gas. A dense ZrO 2 -CeO 2 coating with a thickness of 50 μm was formed, whereas spraying milled ZrO 2 powder can only lead to an inhomogeneous dispersion of the destructible particles on the surface of the substrate.

Description: Laser surface alloying (LSA), with Wallex-50 and Tribaloy-700 powders, and laser transformation hardening (LTH) reduced the silt erosion rate in 16Cr-5Ni steel. Slurry erosion wear tests were conducted on 16Cr-5Ni steel, LSA-modified steel, and LT-hardened steel at different angles of impingement and velocities at a constant size of silica particles. The LSA-modified steel and LT-hardened steel showed improved wear resistance by about 1.5-3 times as compared to substrate 16Cr-5Ni steel for all angles of impingement. This improvement in hardness and erosion resistance was due to the incorporation of carbides and hard complex phases after LSA and LTH.

Description: In this study, an artificial neural network (ANN) was employed to predict the contact fatigue life of alloy cast steel rolls (ACSRs) as a function of alloy composition, heat treatment parameters, and contact stress by utilizing the back-propagation algorithm. The ANN was trained and tested using experimental data and a very good performance of the neural network was achieved. The well-trained neural network was then adopted to predict the contact fatigue life of chromium alloyed cast steel rolls with different alloy compositions and heat treatment processes. The prediction results showed that the maximum value of contact fatigue life was obtained with quenching at 960 °C, tempering at 520 °C, and under the contact stress of 2355 MPa. The optimal alloy composition was C-0.54, Si-0.66, Mn-0.67, Cr-4.74, Mo-0.46, V-0.13, Ni-0.34, and Fe-balance (wt.%). Some explanations of the predicted results from the metallurgical viewpoints are given. A convenient and powerful method of optimizing alloy composition and heat treatment parameters of ACSRs has been developed.

Description: The hot deformation behavior of AMS 5708 nickel-based superalloy was investigated by means of hot compression tests and a processing map in the temperature range of 950-1200 °C and a strain rate range of 0.01-1 s −1 was constructed. The true stress-true strain curves showed that the maximum flow stress decreases with the increase of temperature and decrease of strain rate. The developed processing map based on experimental data, showed variations of efficiency of power dissipation relating to temperature and strain rate at constant strain. Interpretation of the processing map showed one stable domain, in which dynamic recrystallization was the dominant microstructural phenomenon, and one instability domain with flow localization. The results of interpretation of flow stress curves and processing map were verified by the microstructure observations. There are two optimum conditions for hot working of this alloy with efficiency peak of 0.36: the first is at 1150 °C for a strain rate of 1 s −1 that produces a fine grained microstructure. The second is at 1200 °C for a strain rate of 0.01 s −1 that produces a coarse grained microstructure.

Description: Setaria verticillata leaf extract (SVLE) as corrosion inhibitor in 1M H 2 SO 4 was investigated by weight loss techniques and electrochemical techniques at 308-328 K. Inhibition efficiency of SVLE was found to increase with increasing concentration but decreased with temperature. Polarization measurements revealed that SVLE acted as mixed-type inhibitor. Impedance diagrams showed that increasing of SVLE concentration increased charge transfer resistance and decreased double layer capacitance. The adsorption of SVLE on the mild surface obeyed the Langmuir adsorption isotherm. Protective film formation against corrosion was confirmed by SEM and FTIR.

Description: Nickel-iron-based alloy 718 was thermally exposed in peak-aged condition at 550 and 650 °C, from 5 to 100 h, with and without salt coatings and was tested in tension at room temperature and elevated temperatures. Standard tensile specimens were coated with three different salts (in wt.%): NaCl(100), Na 2 SO 4  + NaCl (75/25), and Na 2 SO 4  + NaCl + V 2 O 5 (90/5/5). Exposure of salt-coated specimens at 550 and 650 °C revealed formation of scales and corrosion pits. Tensile deformation resulted in cracking of the surface oxide/corrosion scale. The uncoated specimens showed formation of oxide scales on the surface, without any cracking whereas the salt-coated specimens showed surface cracking and pitting at some places. However, tensile properties were not degraded due to salt coatings.

Description: Platinum nanoparticles were deposited on boron-doped diamond substrate by electroless method without pre-activation. The mechanism of this deposition is a galvanic process along with a chemical process. Platinum particles are in nanoscale with diameter around 30-50 nm and height of around 3 nm observed from AFM and SEM images. The electrochemical activity of Pt nanoparticles was evaluated by cyclic voltammograms of hydrogen desorption process in 0.5 M H 2 SO 4 . The deposited platinum shows great stability in subsequent cycling in sulfuric acid and exhibits a high selectivity toward H 2 O 2 detection in the range of 1 to 400 μM compared with those produced by electrochemical deposition.

Description: This paper presents the results obtained with a new ball burnishing tool developed for the mechanical treatment of large flat surfaces. Several parameters can affect the mechanical behavior and fatigue of workpiece. Our study focused on the effect of the burnishing force on the surface quality and on the service properties (mechanical behavior, fatigue) of AISI 1010 steel hot-rolled plates. Experimental results assert that burnishing force not exceeding 300 N causes an increase in the ductility. In addition, results indicated that the effect of the burnishing force on the residual surface stress was greater in the direction of advance than in the cross-feed direction. Furthermore, the flat burnishing surfaces did not improve the fatigue strength of AISI 1010 steel flat specimens.

Description: K IA is increasingly being regarded as a characteristic fracture toughness below which cleavage fracture does not occur. Its evaluation from small-sized Charpy specimens would be advantageous for applications in power plant industries. In this study, K IA has been evaluated for P91 steel in various cold worked and thermally aged conditions. Evaluation of K IA requires determination of crack arrest load( P arrest ) and crack arrest length( a arrest ). The main challenge is in the determination of a arrest due to the non-availability of standard methodologies and the absence of unequivocal microstructural signatures on the fracture surface in this steel to identify crack arrest. a arrest has been determined using the analytical Key - Curve methodology which has proven successful for this steel in unaged condition. The applicability of the Key - Curve method is validated by the good agreement of the determined final crack length with that measured optically on unbroken specimens of N&T and subsequently 15% cold-worked P91 steel which had been previously aged at 650 °C for 5000 h. Mean K IA varies from 47.46 MPa√m (NT steel aged at 600 °C for 5000 h) to 69.85 MPa√m(NT + 15% cw steel aged at 650 °C for 10000 h) for the various cold worked and aged datasets. K IA is found to be an average property unlike initiation toughness ( K Jd ) which shows statistical scatter. Mean K IA is found to be in reasonable agreement with the lower bound values of cleavage initiation toughness ( K Jd ) for the datasets in this study.

Description: We produced graphite nanoplatelets (GNP)/silicone resin composites at various loadings. The utilized GNPs were characterized by two-dimensional structure with high aspect ratio (~1810), and the GNP with approximately 10-30 nm thickness and 10-50 µm in length evenly dispersed throughout the resin matrix, which enables that GNPs effectively act as thermally conductive medium, thus contributed considerably to the formation of an efficient three-dimensional network for heat flow. The thermal conductivities of 5, 10, 15, and 20 wt.% GNP composite were 0.35, 1.02, 1.32, and 2.01 W/(m K), and were ca. 0.9, 4.7, 6.3, and 10.2 times higher than that of silicone resin at room temperature, respectively. The thermal conductivity decreased with elevated temperature in 25-200 °C, which was reminiscent at higher loading. Differential scanning calorimeter analysis showed that GNP addition increased the curing temperature of silicone resin from 90 to 119 °C, probably by hindering the free movement (mobility) of the silicone chains. The result showed that the GNP not only reduced the CTE but also improved the thermal stability of composite simultaneously.

Description: In the present work, tailor friction stir welded blanks (TFSWBs) were fabricated successfully using 2.0-mm-thick AA5754-H22 and AA5052-H32 sheet metals with optimized tool design and process parameters. Taguchi L9 orthogonal array has been used to design the friction stir welding experiments, and the Grey relational analysis has been applied for the multi objective optimization in order to maximize the weld strength and total elongation reducing the surface roughness and energy consumption. The formability of the TFSWBs and parent materials was evaluated and compared in terms of limiting drawing ratio (LDR) using a conventional circular die. It was found that the formability of the TFSWBs was comparable with that of both the parent materials without failure in the weldment. A modified conical tractrix die (MCTD) was proposed to enhance the LDR of the TFSWBs. It was found that the formability was improved by 27% using the MCTD.

Description: The initial corrosion behavior of carbon steel subjected to Shenyang industrial atmosphere has been investigated by weight-loss measurement, scanning electron microscopy observation, x-ray diffraction, auger electron spectroscopy, and electron probe microanalysis. The experimental results reveal that the corrosion kinetics of the initial corrosion of carbon steel in industrial atmosphere follows empirical equation D  =  At n , and there is a corrosion rate transition from corrosion acceleration to deceleration; the corrosion products are composed of γ -FeOOH, α -FeOOH, Fe 3 O 4 , as well as FeS which is related to the existence of sulfate-reducing bacteria in the rust layers. The effect of dust particles on the corrosion evolution of carbon steel has also been discussed.

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: An improved high-cycle multiaxial fatigue criterion based on the critical plane was proposed in this paper. The critical plane was defined as the plane of maximum shear stress (MSS) in the proposed multiaxial fatigue criterion, which is different from the traditional critical plane based on the MSS amplitude. The proposed criterion was extended as a fatigue life prediction model that can be applicable for ductile and brittle materials. The fatigue life prediction model based on the proposed high-cycle multiaxial fatigue criterion was validated with experimental results obtained from the test of 7075-T651 aluminum alloy and some references.

Description: Simulation of hot stamping process needs reliable material data, especially at high temperatures where plastic deformation takes place in austenitic microstructure. In the current study, high-temperature non-isothermal compression tests (NICT) at different ranges of temperature, strain and strain rate as well as constitutive modeling of the flow curves were carried out. The Johnson-Cook and the Nemat-Nasser phenomenological models for isothermal deformation conditions were revised and applied to fit the flow curves during high-temperature NICT. It was shown that the models can satisfactorily predict the material flow stress at the mentioned conditions. Furthermore, the models were employed in order to describe the work-hardening behavior of the material. The results indicated that the fitted work-hardening rate can successfully follow the experimental data during deformation till no strain-induced phase transformation is initiated.

Description: This study aims to examine the effect of annealing conditions on nitinol (NiTi) characteristics and applies this knowledge to fabricate a NiTi-copper shape memory alloy bimorph actuator. The effect of the annealing conditions was investigated at various temperatures, i.e., 500, 600, and 650 °C, for 30 min. With the characterizations using x-ray diffraction, energy dispersive spectroscopy, and differential scanning calorimetry techniques, the results showed that annealing temperatures at 600 and 650 °C were able to appropriately form the crystalline structure of NiTi. However, at these high annealing temperatures, the oxide on a surface was unavoidable. In the fabrication of actuator, the annealing at 650 °C for 30 min was chosen, and it was performed at two pre-stressing conditions, i.e., straight and curved molds. From static and dynamic response experiments, the results suggested that the annealing temperature significantly affected the deflection of the actuator. On the other hand, the effect of pre-stressing conditions was relatively small. Furthermore, the micro gripper consisting of two NiTi-copper bimorph actuators successfully demonstrated for the viability of small object manipulation as the gripper was able to grasp and hold a small plastic ball with its weight of around 0.5 mg.

Description: This study aimed to investigate the formation and effect of a biofilm on copper heat exchangers in full-scale system conditions. A modified Pedersen device with copper coupons was installed in parallel to a heat exchanger system to investigate several physico-chemical parameters, such as bacterial enumeration, carbohydrate content of exopolymeric substances, weight loss of test/control coupons, Cu concentrations, and corrosion products over ten months. Findings of this study showed that planktonic bacterial cells attach to each other and form a mixed-species biofilm on the copper coupon surface even though copper is toxic to a variety of microorganisms. These results also revealed that the mixed-species biofilm has a corrosive effect on copper surfaces used in cooling water systems despite the presence of biocide and the corrosion inhibitor. Additionally, it was demonstrated that a shock-dosed biocide application increased the corrosion rate on copper surface in a real system. Preventing risk of microbiologically influenced corrosion entails appropriate material selection and proper/regular chemical treatment of cooling systems. The current study provides useful insights through the evaluation of corrosion of materials with microbiological techniques.

Description: The present work concentrates on the analysis of wear behavior of bainitic steels made by austempering from a microalloyed steel MAS2, meant for making railway wheel, and comparison with that of a conventional railway wheel steel, wheel-R19. Austempering of the MAS2 steel samples has been performed at different times and temperatures to obtain different morphologies of bainite. Linearly reciprocating dry sliding wear tests of these samples have been carried out at laboratory scale using five different loads. The wear behavior of the bainitic steels has been compared with that of the ferritic-pearlitic steel, wheel-R19. Mechanical properties of the bainitic MAS2 steels are found to be more than that of the wheel-R19 steel. Considerable enhancement in wear resistance of the bainitic steels is attributed to high hardness and strength of the steels. The wear mechanism has been critically analyzed by examining wear track morphology. The wear data gathered have been graphically presented in the form of wear mechanism map to understand the material behavior under different sliding conditions and subsequent morphological variations.

Description: In this paper, sphere-like (Y 1− x Eu x ) 2 O 3 nanocrystalline particles with ( x  = 0.02;0.05;0.06;0.07;0.08, and 0.09) were obtained by the urea-based homogeneous precipitation technology followed by low-temperature crystallization from 600 to 900 °C. The structure and morphology of the (Y 1− x Eu x ) 2 O 3 nanocrystalline particles and thermal stability of the nanocrystalline particles were investigated by means of transmission electron microscopy and x-ray diffraction analysis. The structural evaluation was established in relation to thermal conditions of sphere crystallization to ensure maximally effective luminescence of Eu 3+ ions ( 5 D 0  →  7 F 2 transitions) with the morphological stability, the spherical shape of individual nanocrystalline particles remaining unchanged. The crystalline nanospheres were shown to have the threshold of concentration quenching of luminescence shifted toward lower concentrations of Eu 3+ ions in comparison with micropowders of analogous composition. That may be caused by the formation of (Y 1− x Eu x ) 2 O 3 composition with the concentration gradient of Eu 3+ , followed by accumulation of Eu 3+ ions around the grain boundaries.

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:    The effect of NaOH content of electrolyte on the properties of ceramic coatings, produced in silicate solution, was studied. Morphology, chemical analysis, phase composition, and cross-section of the ceramic coatings were investigated by SEM, EDS, XRD, and OM, respectively. The corrosion resistance and corrosion mechanism were also studied using potentiodynamic polarization and electrochemical impedance spectroscopy in a 3.5% NaCl solution. To study the surface roughness, a brightness SEM image analysis method was used. Results suggested that increasing the NaOH concentration of sediment production size causes thickness and coating roughness to decrease. The lowest corrosion rate belonged to the twofold layer coating produced in 10 g/L of NaOH. Other samples, with higher concentrations of NaOH, had reduced porosity, and thus an increase in the corrosion resistance was observed. These coatings mainly consisted of α/γ-Al 2 O 3 and amorphous silica. Content Type Journal Article Pages 1-8 DOI 10.1007/s11665-012-0151-1 Authors D. Salehi Doolabi, Department of Materials Science and Engineering, Faculty of Engineering, Shahid Bahonar University of Kerman, P.O. Box 76175-133, Islamic Republic Blvd., Kerman, Iran M. Ehteshamzadeh, Department of Materials Science and Engineering, Faculty of Engineering, Shahid Bahonar University of Kerman, P.O. Box 76175-133, Islamic Republic Blvd., Kerman, Iran S. M. M. Mirhosseini, Faculty of Materials Science and Engineering, Sharif University of Technology, Tehran, Iran Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    In this study, the electric resistance spot welding process was applied to zinc-coated steel sheets used in automotive industry. Spot welding parameters namely, electrode form, electrode material, and electrode force were stayed constant, and welding current and welding time have been changed to detect the optimum welding parameters for maximum joint strength. Using 4, 5, 6, 7, and 8 kA welding currents and 5, 10, 15, 20, and 25 cycles welding times 1.0-1.0 mm sheets were spot welded to prepare samples. These spot-welded joints were then exposed to uniaxial tensile test, and tensile-shear and tensile-peel forces prior to breaking were determined. In addition, microstructures were detected by SEM and micro-hardness was measured from different regions of resistance spot-welded samples and recommendations showing the optimum welding parameters were given to users. Content Type Journal Article Pages 1-8 DOI 10.1007/s11665-012-0189-0 Authors Ugur Ozsarac, Department of Metallurgical and Materials Engineering, Technology Faculty, Sakarya University, Sakarya, Turkey Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    Strain aging and hardening behaviors of a 304 stainless steel containing deformation-induced martensite were investigated by examining mechanical properties and microstructural evolution for different aging temperature and time. Introduced age hardening mechanisms of a cold rolled 304 stainless steel were the additional formation of α′-martensite, hardening of α′-martensite, and hardening of deformed austenite. The increased amount of α′-martensite at an aging temperature of 450 °C confirmed the additional formation of α′-martensite as a hardening mechanism in a cold rolled 304 stainless steel. Additionally, the increased hardness in both α′-martensite and austenite phases with aging temperature proved that hardening of both α′-martensite and austenite phases would be effective as hardening mechanisms in cold rolled and aged 304 stainless steels. The results suggested that among hardening mechanisms, hardening of an α′-martensite phase, including the diffusion of interstitial solute carbon atoms to dislocations and the precipitation of fine carbide particles would become a major hardening mechanism during aging of cold rolled 304 stainless steels. Content Type Journal Article Pages 1-6 DOI 10.1007/s11665-012-0186-3 Authors S. W. Jeong, School of Advanced Material Engineering, Kookmin University, 861-1 Jeongneung-Dong, Songbuk-Ku, Seoul, 136-702 Republic of Korea U. G. Kang, School of Advanced Material Engineering, Kookmin University, 861-1 Jeongneung-Dong, Songbuk-Ku, Seoul, 136-702 Republic of Korea J. Y. Choi, Stainless Steel Research Group, POSCO Technical Research Laboratories, POSCO, P.O. Box 36, Pohang, 790-785 Republic of Korea W. J. Nam, School of Advanced Material Engineering, Kookmin University, 861-1 Jeongneung-Dong, Songbuk-Ku, Seoul, 136-702 Republic of Korea Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    This study investigates the microstructure, electrical, corrosion, and mechanical properties of plate-shaped aluminum-copper couple produced using the explosive welding method. Mechanical tests, including hardness, tensile, tensile-shear, and impact test, concluded that the Al-Cu bimetal had an acceptable joint resistance. In this study, local intermetallic regions formed on the interface of the joint of the aluminum-copper bimetal, produced using the explosive welding technique. However, the formed intermetallic regions had no significant effect on the mechanical properties of the joint, except for increasing its hardness. According to electrical conductivity tests, the Al-Cu bimetal had an average electrical conductivity in comparison to the electrical conductivity of aluminum and copper, which were the original materials forming the joint. According to the results of electro-chemical corrosion test, during which galvanic corrosion formed, the Al side of the Al-Cu bimetal was more anodic due to its high electronegativity; as a result, it was exposed to more corrosion in comparison to the copper side. Content Type Journal Article Pages 1-5 DOI 10.1007/s11665-012-0203-6 Authors Mustafa Acarer, Technical Education Faculty, Karabuk University, 78100 Karabuk, Turkey Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    Ti and its alloys are widely used in manufacturing orthopedic implants as prostheses for joint replacement because of their high corrosion resistance and excellent biocompatibility. However, they lack in bone-bonding ability and leads to higher rate of osteolysis and subsequent loosening of implants. In order to enhance the bone-bonding ability of these alloys, various surface-modification techniques are generally employed. The present investigation is mainly concerned with the surface modification of Cp-Ti and Ti-5Al-2Nb-1Ta alloy using a mixture of alkali and hydrogen peroxide followed by subsequent heat treatment to produce a porous gel layer with anatase structure, which enhances osseointegration. The morphological behavior was examined by x-ray diffractometer (XRD), atomic force microscopy (AFM), and scanning electron microscopy (SEM) coupled with energy dispersive x-ray analysis (EDX). The in vitro characterization of all the specimens was evaluated by immersing the specimens in simulated body fluid solution to assess the apatite formation over the metal surface. The apatite formation was confirmed by XRD, SEM-EDX, and Fourier transform infrared spectroscopy (FT-IR). Further, the electrochemical corrosion behaviors of both the untreated and treated specimens were evaluated using potentiodynamic polarization and electrochemical impedance spectroscopy. The results revealed that the surface-modified and heat-treated specimens exhibited higher corrosion resistance and excellent biocompatibility when compared to the chemical and untreated specimens. Content Type Journal Article Pages 1-11 DOI 10.1007/s11665-012-0143-1 Authors Y. Sasikumar, Department of Chemistry, Anna University, Chennai, 600 025 India N. Rajendran, Department of Chemistry, Anna University, Chennai, 600 025 India Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    This study investigates the mechanical properties of Al-7Si-0.3Mg (A356) alloy affected by the spinning deformation processing (SDP). The cast structure of the A356 alloy becomes elongated with increasing reduction in thickness. This leads to reduction of casting defects, and refines and distributes the eutectic silicon phase throughout the Al-matrix. The hardness tends to reach a steady value due to the uniformity of the microstructure with the reduction in thickness. The SDP leads to a re-arrangement in the eutectic region, which forces the propagation of cracks through the ductile α-Al phase. The tensile strength and elongation increases accordingly. The improvement on tensile strength and elongation produces the best quality index for A356 alloy. Content Type Journal Article Pages 1-6 DOI 10.1007/s11665-011-0089-8 Authors Yin-Chun Cheng, Department of Mechanical Engineering, National Central University, No. 300, Jhongda Rd., Jhongli City, Taoyuan County 32001, Taiwan, ROC Chih-Kuang Lin, Department of Mechanical Engineering, National Central University, No. 300, Jhongda Rd., Jhongli City, Taoyuan County 32001, Taiwan, ROC An-Hung Tan, Department of Mechanical Engineering Ching-Yun University, No. 229, Jianxing Rd., Zhongli City, Taoyuan County 32097, Taiwan, ROC Shih-Yuan Hsu, Department of Mechanical Engineering, National Central University, No. 300, Jhongda Rd., Jhongli City, Taoyuan County 32001, Taiwan, ROC Sheng-Long Lee, Department of Mechanical Engineering, National Central University, No. 300, Jhongda Rd., Jhongli City, Taoyuan County 32001, Taiwan, ROC Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    Alumina ceramic foams have been infiltrated with an Al-10 Mg alloy, by a capillarity-driven process, to create interpenetrating composites. Infiltration maps are presented for three different foam types which depict the temperature and time required for successful infiltration. The Young’s modulus of “fully” infiltrated composites containing approximately 18, 25, and 36 vol.% ceramic were measured and found to be 96, 110, and 124 GPa, respectively. Porosimetry of the foams revealed a significant fraction of closed porosity within the cell walls, the quantity of which increases with foam density, which accounts for the lower density and stiffness values that were measured, compared with those predicted by a simple model. Content Type Journal Article Pages 1-7 DOI 10.1007/s11665-012-0147-x Authors R. Gil, Facultad de Ingeniería, Universidad de Los Andes, Mérida, Venezuela A. R. Kennedy, Manufacturing Research Group, Faculty of Engineering, University of Nottingham, Nottingham, NG7 2RD UK Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    A combination of the transverse tensile test and the unilaterally coupled finite element method was used to evaluate the interfacial normal bond strength and stress distribution of titanium matrix composites (TMCs). In addition, in order to identify the interface shear failure mode of TMCs under transverse loading, both the push-out test and the finite element method have been developed to characterize the interfacial shear strength of TMCs, which is the interfacial shear failure criterion. This article studies the results of the experiments, which suggested that the interfacial normal bond and shear strength of SiC f /Ti-6Al-4V were 300 and 350 MPa, respectively, and the interface failure mode of TMCs under the transverse tensile test was radial failure rather than shear failure. Moreover, the effect of residual stress on the radial stress is also discussed in detail in this article. Content Type Journal Article Pages 1-5 DOI 10.1007/s11665-011-0094-y Authors Xu Yanfang, College of Mechanical and Electrical Engineering, North University of China, Taiyuan, 030051 People’s Republic of China Su Tiexiong, College of Mechanical and Electrical Engineering, North University of China, Taiyuan, 030051 People’s Republic of China Yuan Meini, College of Mechanical and Electrical Engineering, North University of China, Taiyuan, 030051 People’s Republic of China Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    In the present work, cladding of hardfacing WC10Co2Ni powder on austenitic stainless steel has been developed through a novel processing technique. The clads were developed using microwave hybrid heating. The clad of average thickness ~2 mm has been developed through the exposure of microwave radiation at frequency 2.45 GHz and power 900 W for the duration of 360 s. The developed clads were characterized using field emission scanning electron microscope, X-ray elemental analysis, X-ray diffraction, and measurement of Vicker’s microhardness. The microstructure study of the clad showed good metallurgical bonding with substrate and revealed that clads are free from any visible interface cracking. Clads were formed with partial dilution of a thin layer of the substrate. The cermet microstructure mainly consists of relatively soft metallic matrix phase and uniformly distributed hard carbide phase with skeleton-like structure. The developed clads exhibit an average microhardness of 1064 ± 99 Hv. The porosity of developed clad has been significantly less at approximately 0.89%. Content Type Journal Article Pages 1-8 DOI 10.1007/s11665-012-0142-2 Authors Dheeraj Gupta, Department of Mechanical and Industrial Engineering, Indian Institute of Technology Roorkee, Roorkee, 247667 India Apurbba Kumar Sharma, Department of Mechanical and Industrial Engineering, Indian Institute of Technology Roorkee, Roorkee, 247667 India Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    The purpose of this test was to evaluate the effects of calcium magnesium acetate (CMA) and sodium chloride (NaCl)—two common substances used to de-ice roadways—on the corrosion and fatigue behavior of annealed AISI 4140 steel. When CMA-corroded, NaCl-corroded, and as-machined samples were tested using R  = 0.1, and f  = 20 Hz, it was found that, within the scope of this study, samples corroded in both 3.5% CMA solution and 3.5% NaCl solution exhibited a lower fatigue strength than samples tested in the as-machined, uncorroded condition. For the short lives tested in this study, the difference in the effects of CMA and NaCl is minimal. However, at longer lives it is suspected, based on the trends, that the CMA solution would be less detrimental to the fatigue life. Content Type Journal Article Pages 1-5 DOI 10.1007/s11665-012-0167-6 Authors William P. Dean, Department of Mechanical and Aerospace Engineering, University of Alabama in Huntsville, Huntsville, AL 35899, USA Brittain J. Sanford, Department of Mechanical and Aerospace Engineering, University of Alabama in Huntsville, Huntsville, AL 35899, USA Matthew R. Wright, Department of Mechanical and Aerospace Engineering, University of Alabama in Huntsville, Huntsville, AL 35899, USA Jeffrey L. Evans, Department of Mechanical and Aerospace Engineering, University of Alabama in Huntsville, Huntsville, AL 35899, USA Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    In the present investigation, the correlation of composition-processing-property for TC11 titanium alloy was established using principal component analysis (PCA) and artificial neural network (ANN) based on the experimental datasets obtained from the forging experiments. During the PCA step, the feature vector is extracted by calculating the eigenvalue of correlation coefficient matrix for training dataset, and the dimension of input variables is reduced from 11 to 6 features. Thus, PCA offers an efficient method to characterize the data with a high degree of dimensionality reduction. During the ANN step, the principal components were chosen as the input parameters and the mechanical properties as the output parameters, including the ultimate tensile strength ( \upsigma \text b ), yield strength ( \upsigma 0.2 ), elongation ( \updelta ), and reduction of area (φ). The training of ANN model was conducted using back-propagation learning algorithm. The results clearly present ideal agreement between the predicted value of PCA-ANN model and experimental value, indicating that the established model is a powerful tool to construct the correlation of composition-processing-property for TC11 titanium alloy. More importantly, the integrated method of PCA and ANN is also able to be utilized as the mechanical property prediction for the other alloys. Content Type Journal Article Pages 1-7 DOI 10.1007/s11665-012-0162-y Authors Yu Sun, State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an, 710072 People’s Republic of China Weidong Zeng, State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an, 710072 People’s Republic of China Yongqing Zhao, Northwest Institute for Nonferrous Metal Research, Xi’an, 710016 People’s Republic of China Yitao Shao, State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an, 710072 People’s Republic of China Yigang Zhou, State Key Laboratory of Solidification Processing, 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 forming limit diagram (FLD) is a useful method for characterizing the formability of sheet metals. In this article, different numerical models were used to investigate the FLD of tailor-welded blank (TWB). TWBs were CO 2 laser-welded samples of interstitial-free (IF) steel sheets with difference in thickness. The results of the numerical models were compared with the experimental FLD as well as with the empirical model proposed by the North American Deep Drawing Research Group. The emphasis of this investigation is to determine the performance of these different approaches in predicting the FLD. These numerical models for FLD are: second derivative of thinning (SDT), effective strain rate (ESR), major strain rate (MSR), thickness strain rate (TSR), and thickness gradient (TG). Results of this research show necking will be happened, when the value of MSR, TSR, ESR criteria is maximum, TG ≤ 0.78 and SDT criterion has the first peak in forming process time. The value of dome height of TWB samples at failure was predicted based on the numerical models for samples with different widths. These numerical predictions were compared with the experimental results. The SDT model indicates a better agreement with experimental results in prediction of both the FLD and the limit dome height (LDH) in comparison to the other numerical models. Both numerical and experimental results show that minimum of LDH is happened in plane strain condition. Content Type Journal Article Pages 1-9 DOI 10.1007/s11665-012-0156-9 Authors Rasoul Safdarian Korouyeh, Tarbiat Modares University, Jalal Ale Ahmad Highway, P.O. Box 14115-143, Tehran, Iran Hassan Moslemi Naeini, Tarbiat Modares University, Jalal Ale Ahmad Highway, P.O. Box 14115-143, Tehran, Iran Gholamhosein Liaghat, Tarbiat Modares University, Jalal Ale Ahmad Highway, P.O. Box 14115-143, Tehran, Iran Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    This article describes attempts to characterize by standardized tests of tile materials used in the construction area the performance-based properties of foamed glass samples with novel glass coatings. New glass coated foam glass (Foamglas ® ) insulating tiles have been tested by several standard tests (UNI Iso, ASTM) to define their suitability for energy saving buildings: impact tests, thermal shock resistance, wear resistance, water absorption, frost resistance, resistance to stains. Except for impact tests, glass coated foam glass (Foamglas ® ) satisfied all the requirements above, resulting to be thermal shock resistant, according to Uni Iso 10545-9 (Al spheres); effective to reduce the pristine Foamglas ® surface water absorption, according to Uni En 1609:1999 and 12087:1999; frost resistant, according to Uni Iso 10545-12 and class 5 towards olive oil, according to Uni Iso 10545-14. Wear tests and hot water corrosion behavior tests have been done on the proposed coating and on a commercial soda-lime glass: the glass coated foam glass resulted to be suitable where corrosion and wear resistance are not a concern. Content Type Journal Article Pages 1-9 DOI 10.1007/s11665-012-0164-9 Authors Andrea Ventrella, Materials Science and Chemical Engineering Department, Politecnico di Torino, Corso Duca Degli Abruzzi 24, 10129 Torino, Italy Federico Smeacetto, Materials Science and Chemical Engineering Department, Politecnico di Torino, Corso Duca Degli Abruzzi 24, 10129 Torino, Italy Milena Salvo, Materials Science and Chemical Engineering Department, Politecnico di Torino, Corso Duca Degli Abruzzi 24, 10129 Torino, Italy Monica Ferraris, Materials Science and Chemical Engineering Department, Politecnico di Torino, Corso Duca Degli Abruzzi 24, 10129 Torino, Italy Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495

Description:    In order to produce shape memory rings for constrained-recovery pipe couplings, from Fe-14 Mn-6 Si-9 Cr-5 Ni (mass%) powders, the main technological steps were (i) mechanical alloying, (ii) sintering, (iii) hot rolling, (iv) hot-shape setting, and (v) thermomechanical training. The article generally describes, within its experimental-procedure section, the last four technological steps of this process the primary purpose of which has been to accurately control both chemical composition and the grain size of shape memory rings. Details of the results obtained in the first technological step, on raw powders employed both in an initial commercial state and in a mixture state of commercial and mechanically alloyed (MA) powders, which were subjected to several heating-cooling cycles have been reported and discussed. By means of differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and X-ray diffraction (XRD), the thermal behaviors of the two sample powders have been analyzed. The effects of the heating-cooling cycles, on raw commercial powders and on 50% MA powders, respectively, were argued from the point of view of specific temperatures and heat variations, of elemental diffusion after thermal cycling and of crystallographic parameters, determined by DSC, SEM, and XRD, respectively. Content Type Journal Article Pages 1-10 DOI 10.1007/s11665-012-0168-5 Authors B. Pricop, Faculty of Materials Science and Engineering, The “Gheorghe Asachi” Technical University from Iaşi, Bd. D. Mangeron 61A, 700050 Iasi, Romania U. Söyler, Particulate Materials Laboratory, Metallurgical and Materials Engineering Department, Istanbul Technical University, 34469 Maslak, Istanbul, Turkey N. M. Lohan, Faculty of Materials Science and Engineering, The “Gheorghe Asachi” Technical University from Iaşi, Bd. D. Mangeron 61A, 700050 Iasi, Romania B. Özkal, Particulate Materials Laboratory, Metallurgical and Materials Engineering Department, Istanbul Technical University, 34469 Maslak, Istanbul, Turkey L. G. Bujoreanu, Faculty of Materials Science and Engineering, The “Gheorghe Asachi” Technical University from Iaşi, Bd. D. Mangeron 61A, 700050 Iasi, Romania D. Chicet, Faculty of Mechanical Engineering, The “Gheorghe Asachi” Technical University from Iaşi, Bd. D. Mangeron 61-63, 700050 Iasi, Romania C. Munteanu, Faculty of Mechanical Engineering, The “Gheorghe Asachi” Technical University from Iaşi, Bd. D. Mangeron 61-63, 700050 Iasi, Romania Journal Journal of Materials Engineering and Performance Online ISSN 1544-1024 Print ISSN 1059-9495