LI Jia-yan, LI Chao-chao, LI Ya-qiong, TAN Yi. Electrochemical Separation of Aluminum-silicon Alloy at Low Temperature During Si Solidification Refining Process[J]. Journal of Materials Engineering, 2013, 0(11): 1-5,11.
The electrochemical separation of aluminum-silicon alloy in the low temperature molten salt AlCl3-NaCl-KCl at constant current deposition was studied. Aluminum-silicon alloy for the anode electrode and stainless steel for the cathode electrode were used. The effects of temperature, current density and time on the current efficiency and the morphology of deposited aluminum were analyzed by the scanning electron microscope and X-ray diffraction. The results show that, when the current density is 50mA/cm2, the maximum current efficiency can reach 93.7% at 200℃ for 60min using Si-50% Al(mass fraction) as anode electrode, and there is 90.4% silicon in the anode slime.
LI Bo, PAN Qing-lin, ZHANG Zhi-ye, LI Chen, YIN Zhi-min. Hot Deformation Behavior and Microstructure of Al-Zn-Mg Alloy Containing Sc During Hot Compression at Elevated Temperature[J]. Journal of Materials Engineering, 2013, 0(11): 6-11.
The hot compression test of Al-Zn-Mg alloy containing Sc was performed on Gleeble-1500 thermal simulation machine. The hot deformation behavior and microstructural evolution of the alloy were investigated under different deformation conditions. The hot deformation temperature and the strain rate during hot compression tests were 340-500℃, 0.001-10s-1, respectively. The results show that the flow stress of the alloy increase with the increasing the strain rate, but decrease with the increasing of the deforming temperature. The flow stress of the alloy during hot compression deformation can be described by a Zener-Hollomon parameter. The hot deformation activation energy is 150.25kJ/mol. When the deformation temperature is 380℃ and the strain rates is 1s-1, the dislocation walls formed and the main soften mechanism is dynamic recovery. When the deformation temperature is 500℃, the recrystallization grains are observed, indicating that the main soften mechanism of the alloy transform from dynamic recovery to dynamic recrystallization.
YUAN You-lu, LI Zhu-guo. Dissolving and Precipitating Characteristics of WC and Carbides in the Ni60A+WC Graded Coating[J]. Journal of Materials Engineering, 2013, 0(11): 12-19,25.
The dissolution and precipitation of WC in the multilayered Ni60A+WC reinforced Fe-based graded coating fabricated by Plasma cladding were studied, in which the content of Ni60A+WC increased by 10%mass fraction layer by layer. The results show that the dissolution of WC in each layer of the graded coating during the plasma cladding heating stage was closely related to the particle size and inner defect. The dissolution characteristics of WC are classified into four types: diffusing, core dissolution, crumbling, and diffusing complex core-dissolution. The shape characteristics of the precipitated W-rich carbides in the graded coating during the solidification process are relevant to the contents of Ni60A+WC. With the increasing of the contents for the Ni60A+WC from 10% to 50%, the shapes of W-rich carbides are transferred from reticulation, grain, grain mixed with block, block mixed with cluster to big block mixed with equiaxial structures, and the quantity of the precipitated W-rich carbides increased layer by layer. As a result, the hardness of the graded coating linearly increases gradually.
DAI Shi-juan, WANG Yu, CHEN Feng, YU Xin-quan, ZHANG You-fa. Effect of Annealing Process on Microstructure and Mechanical Properties of Cold Rolled Ti-35Nb-9Zr-6Mo-4Sn Biomedical Titanium Alloy with Large Reduction[J]. Journal of Materials Engineering, 2013, 0(11): 20-25.
The microstructure and mechanical properties of the new biomedical titanium alloy Ti-35Nb-9Zr-6Mo-4Sn after solution treatment, 85% cold rolled deformation and recrystallization annealing were investigated. The results showed that the alloy was composed of the single β phase after solution treatment and 85% cold rolled deformation. Cold deformation made the strength increased significantly, the elastic modulus reduced and the elongation decreased slightly. The alloy was still composed of the single β phase and the grain refined significantly after recrystallization annealing at 650℃. With the holding time increasing, the defect reduced, the recrystallization ratio increased, leading to the slight decrease of the strength, the increase of the elastic modulus and the significant improvement of the plasticity. Cold rolled Ti-35Nb-9Zr-6Mo-4Sn alloy with the reduction of 85% after annealing at 650℃ for 30-60min, whose strength and elongation was superior to that of Ti-6Al-4V, had excellent comprehensive mechanical properties, which was suitable for a kind of medical implant material.
LIU Xiu-bo, LIU Hai-qing, MENG Xiang-jun, YANG Mao-sheng, SHI Shi-hong, FU Ge-yan, SUN Cheng-feng, WANG Ming-di, QI Long-hao. High Temperature Tribological Behaviors of Laser Cladding NiCr/Cr3C2-WS2 Self-lubrication Wear-resistant Coating[J]. Journal of Materials Engineering, 2013, 0(11): 26-31,37.
The self-lubricating wear-resistant NiCr/Cr3C2-30%WS2 coating and wear-resistant NiCr/Cr3C2 coating were fabricated by laser cladding on 0Cr18Ni9 austenitic stainless steel. The phase compositions and microstructures were investigated by X-ray diffractometer (XRD), scanning electron microscope (SEM) and energy dispersive spectrometer (EDS). The tribological properties of the fabricated composite coatings were evaluated under dry sliding condition at room-temperature (RT), 300℃ and 600℃, respectively, and the wear mechanisms were discussed. The results show that the phase constituents of coating added with WS2 are composed of Cr7C3, (Cr, W)C reinforcement carbides, ductile phase of γ-(Fe, Ni)/Cr7C3eutectic, and WS2, CrS lubricants. The friction coefficients of above two coatings both decrease with the rising of temperature, but the wear rates both increase. At room-temperature and 300℃, the coating added with WS2 has superior friction-reducing and wear-resistance properties as a result of the presence of WS2 and CrS lubricants. However, the wear rates of two coatings significantly increase due to the hardness reducing of carbides at 600℃.
SHI You-qiang, ZHANG Qiu-yu, HE Shan, WANG Zhi-yong, QI Yu. Synthesis and Properties of Single-component Epoxy Adhesive Containing Microcapsule-type Latent Curing Agent[J]. Journal of Materials Engineering, 2013, 0(11): 32-37.
A novel single-component adhesive was successfully prepared with 2PZ-PGMA microcapsule-type latent curing agent as curing agent and epoxy resin as resin. The optimal composition, optimal curing process, curing characteristics, latent properties and mechanical properties of this single-component adhesive were researched by using DSC and mechanical testing machine. The results show that the one-component adhesive present excellent curing characteristics and latent properties. The E-51/PGMA microcapsule system can be cured at 100℃ in 30min and its shelf life at room temperature is more than 50 days. In addition, the tensile shear strength, compressive strength and impact strength of its casting body are 15.36MPa, 170.67MPa and 5.13×10-3kJ/m2 respectively.
ZHANG Xiao-min, ZHANG Zhen-zhong, ZHAO Fang-xia, QIU Tai. Optimization for Synthesis of High Dispersion Nanosized Silver Powder by Orthogonal Design[J]. Journal of Materials Engineering, 2013, 0(11): 38-42,49.
The Hydrazine hydrate (N2H4·H2O) as the reducing agent, AgNO3 as the source of Ag, the silver nanopowders with good dispersity were prepared by liquid phase reduction method. The morphology, composition and structure of the particles were investigated by transmission electron microscopy (TEM), X-ray fluorescence (XRF), and X-Ray diffraction (XRD), respectively. Single factor experiments were taken by studying the pH value and the selection of dispersers. Using the orthogonal design method, the optimal conditions to prepare the silver nanopowders were obtained by studying the effects of following factors, such as the concentration of AgNO3, the doses of disperser and the temperature on the dispersion of the silver powder. The results show that under optimization conditions, the pure silver nanopowders with near-spherical shapes are synthesized using the AgNO3(0.5mol·L-1), N2H4·H2O (0.5mol·L-1), PVP as disperser, PVP/AgNO3 mass ratio of 9:100, pH=8 at 30℃.
MA Wen-bin, LIU Guo-quan, HU Ben-fu, ZHANG Yi-wen, LIU Jian-tao. Effect of High Temperature Solution Treatment on Carbides in HIPed FGH96 Alloy by Stereology Method[J]. Journal of Materials Engineering, 2013, 0(11): 43-49.
The OM, SEM, TEM and the stereology method were used to observe and quantitatively characterize the carbides in HIPed FGH96 alloys before and after high temperature solution treatment at different temperature. The results show that the carbides in HIPed FGH96 alloy are mainly MC type carbides which are rich in Ti and Nb. The shape of PPB carbides was block, while the non-PPB carbides were petal and block. Compared with the HIPed alloy, the amount of PPB carbides as well as the total carbides in FGH96 alloy increased when the heat treatment temperature was below 1180℃. But the amount of carbides decreased and the PPB gradually disappeared with the increasing temperature when the heat treatment temperature was above 1180℃. The carbides precipitated mainly as non-PPB carbides if the HIPed alloy was furnace cooled. However, such re-precipitation was suppressed when the alloy was air cooled from the heat treatment temperature. Thus, when the alloy was either furnace or air cooled, the amount of PPB carbides was significantly reduced even the total amount of carbides retains almost the same as that in the HIPed alloy in case of furnace cooling. Moreover, the PPB carbide size distribution in the air cooling alloy appears a unimodal mode, while that in the furnace cooling alloy is a bimodal one, the latter of which was resulted from the re-precipitation of carbides occurred in the furnace cooling process.
ZHENG Zhi-teng, YOU Yi-liang, LIU Xin-ling, ZHANG Zheng, LU Hao-tian. Quantitative Reverse Deduction from Fatigue Fracture of TC21 Ti Alloy Joint with Electron Beam Welding[J]. Journal of Materials Engineering, 2013, 0(11): 50-56.
Based on the macroscopical propagation site area and microscopic fatigue striations of the fatigue fracture of titanium alloy joint with electron beam welding, fatigue stress and initial fatigue quality (IFQ) was estimated, respectively. The results show that the area of propagation zone can well estimate the stress at the same fracture toughness. And the relative error can be confined less than 10%. The microscopic characteristic of fatigue crack propagation at the second stage if fatigue striation. The IFQ estimated through Paris formula presents a normal distribution and the results have important engineering significance for the assessment of electron beam welded titanium alloy structure.
WANG Qing, WANG Jing-feng, HUANG Song, LI Lin-jun-nan, GENG Tie, PAN Fu-sheng. Effect of Machining Techniques on Tension-compression Yield Asymmetry of AZ61 Magnesium Alloy[J]. Journal of Materials Engineering, 2013, 0(11): 57-61,88.
Three kinds of machining techniques including one pass extrusion, two passes extrusion and forging after extrusion were adopted to deform AZ61 magnesium alloy, then mechanical property, tension and compression yield asymmetry were studied.The results indicate that, extrusion can refine the grain size of AZ61 magnesium alloy, but the grain is coarse by forging after extrusion. Due to {0002} basal plane orientation strengthened by two passes extrusion, tensile yield strength increases while compressive yield strength decreases, which deteriorate the tension and compression asymmetry. After forging deformation,altering the basal plane texture, while coarsening the grains partly at the same time, tensile yield strength of AZ61 magnesium alloy dropped, while compressive yield strength keep almost the same. As a result, tension and compression yield asymmetry was improved.
ZHOU Jian-qiu, ZHANG Shu, WANG Lu. Shear Band Evolution of Nanocrystalline Ni Under Obvious Plastic Deformation[J]. Journal of Materials Engineering, 2013, 0(11): 62-69,74.
At obvious plastic deformation stage, an in-situ TEM tensile testing for the nanocrystalline Ni was conducted to investigate the microscopic physical mechanisms during the development of shear bands. Thus, a corresponding model was optimized. The results show that in the nanometer scale, with the increasing of grain size, shear band width increases and the trend of strain softening becomes more obvious. The generation of shear band in smaller grain is earlier than that in bigger grain. The intrinsic length scale increases first with the increasing of grain size and then decreases. The distribution of shear strain in shear band is also obtained. The value of shear strain is zero at two boundaries of the shear band and is the maximum at center of the shear band.
SHUI Guo-shuang, HUANG Peng. Nondestructive Evaluation of Surface Plastic Damage for Metallic Material Based on Stress Wave Factor[J]. Journal of Materials Engineering, 2013, 0(11): 70-74.
A method for nonlinear ultrasonic evaluation of surface damage for metallic material is presented. Rayleigh waves are excited and acquired with Ritec SNAP nonlinear ultrasonic measurement system, the FSW-based acoustic nonlinearity parameters (FSW ANPs) are thus measured at different stress levels for AZ31 magnesium alloy plate specimens. The results show that there is a significant increase in the acoustic nonlinearity parameters with monotonic tensile loads when the stress is close to the yielding stress. The research suggests an effective nondestructive evaluation method to track the mechanical property for the surface of metallic material in a nonlinear ultrasonic way using stress wave factor.
LI Jiong-li, ZHANG Kun, XIONG Yan-cai. Advances in Research on Nanocrystalline Al-Mg Alloys with High Performance[J]. Journal of Materials Engineering, 2013, 0(11): 75-80.
Research on the nanostructured Al-Mg alloys wasreviewed. The large increase in strength and drastic decrease in plasticity are commonly observed in nanostructured, Al-Mg alloys. Several approaches were proposed for optimization of strength and ductility simultaneously in nanostructured Al-Mg alloys. Finally Al-Mg alloys with the combination of high strength and acceptable ductility were prepared and developed.
YANG Shao-feng, WANG Zai-you. New Research Development and Its Prospect on Die-cast Magnesium Alloys[J]. Journal of Materials Engineering, 2013, 0(11): 81-88.
The technology of die-cast magnesium alloy, improvement creep resistance and corrosion property, smelting technology, is summarized. The effect of technology of die-cast and alloying elements with smelting technology on creep resistance and corrosion property of die-cast magnesium alloy is analyzed. The subjects are discussed individually and recommendations for further study are listed in the final section.
GAO Zhi-yu, LIU Guo-quan. Recent Progress of Web-enable Material Database and a Case Study of NIMS and MatWeb[J]. Journal of Materials Engineering, 2013, 0(11): 89-96.
Web-enable material database (MDB) is a new model to obtain information based on the development of modern information technology, and is widely used in the fields of new material design; material selection; strategic decision consultation and so on. It is very important to grasp timely the latest tendency of web-enable MDBs and to utilize accurately and efficiently web-enable MDBs for scientific research and engineering application. Consequently the latest developments of web-enable MDBs were introduced in this paper; NIMS and MatWeb, two internationally famous online MDBs, were also studied. The paper expounds it from the following aspects: data service contents; search function; retrieved results processing etc. The aim of this paper is to help researchers select and use web-enable MDBs precisely and efficiently. In the writer's view, the future developments of web-enable MDBs are as follows: one-stop service by web integration; more data types; more data quantities; more standards; as well as more complete information service derived from the database.
