Northwest Institute for Nonferrous Metal Research | Date: 2014-10-08
A method for preparing a porous metal material comprises: in a vacuum environment, volatilizing one or more volatile alloy elements in an alloy, so as to finally form a porous pure metal or a porous alloy. The process method can be widely applied in the fields such as aeronautics and astronautics, atomic energy, electrochemistry, petrochemical industry, metallurgy, machinery, medicines, environmental protection or construction.
Luo J.H.,University of Pittsburgh |
Wu F.F.,Liaoning University of Technology |
Huang J.Y.,Sandia National Laboratories |
Wang J.Q.,Northwest Institute for Nonferrous Metal Research |
Mao S.X.,University of Pittsburgh
Physical Review Letters | Year: 2010
Bulk metallic glasses are brittle and fail with no plastic strain at room temperature once shear bands propagate. How do metallic glasses deform when the size is less than that of shear bands? Here we show that Al90Fe5Ce5 metallic glass with a size <20nm can be extremely elongated to ∼200%. Remarkably, even an atomic chain was formed after sample necking, which was never observed in metallic glasses. The unexpected ductility may originate from the fast surface diffusion and the absence of shear band formation, and may guide the development of ductile metallic glasses for engineering applications. © 2010 The American Physical Society.
Lin C.,Liaoning University of Technology |
Zhao Y.,Northwest Institute for Nonferrous Metal Research |
Yin G.,Liaoning University of Technology
Computational Materials Science | Year: 2014
This article describes a novel calculation method for the lattice constant of solids based on the empirical electron theory (EET) of solids and molecules. This calculation is achieved by introducing the iterative self-consistent method into the bond length difference (BLD) method of EET, called as the self-consistent bond length difference (SCBLD) method. The calculation accuracy of lattice constants with SCBLD method is first evaluated. Moreover, the calculation results in the present article are also compared with the ones calculated with the first principles methods (e.g., SOGGA, PBEsol, WC, AM05, TPSS, PBE) in terms of a set of statistical quantities. The results reveal that SCBLD method can exhibit the excellent calculation accuracy in lattice constants. ©2014 Elsevier B.V. All rights reserved.
Zhang X.,Northwestern Polytechnical University |
Zhao Y.,Northwest Institute for Nonferrous Metal Research |
Zeng W.,Northwestern Polytechnical University
International Journal of Hydrogen Energy | Year: 2010
The influence of hydrogen on microstructure evolution and superplastic behavior of a new near α high-temperature titanium alloy-Ti600 alloy were studied. The results show that hydrogen increases the amount of β phase and δ hydride with fcc structure exists in the specimens when the hydrogen content is over 0.3 wt.%. After hydrogenation, the deformation temperature of Ti600 alloy can be decreased about 80 °C and the strain rate can be increased by at least one order. Addition of proper hydrogen can reduce the flow stress of Ti600 alloy significantly. The flow stress of Ti600-0.5H alloy decreases about 78% of that unhydrogenated Ti600 alloy at 840 °C and 5 × 10-4 s-1. Moreover, introducing hydrogen into Ti600 alloy decreases the dislocation density, promotes the dislocation motion and facilitates the β phase flow. © 2010 Professor T. Nejat Veziroglu.
Zheng Y.-J.,Central South University |
Chen K.-K.,Northwest Institute for Nonferrous Metal Research
Transactions of Nonferrous Metals Society of China (English Edition) | Year: 2014
The leaching kinetics of selenium from selenium-tellurium-rich materials in sodium sulfite solutions was studied. The morphologies of selenium-tellurium- rich materials are mainly spheroid and columnar bodies and the range of particle size of selenium-tellurium-rich materials is between 17.77 μm and 56.58 μm, which contain 41.73% selenium and 40.96% tellurium. The ranges of experimental elements are 126-315 g/L of sodium sulfite concentration, 100-400 r/min of agitation speed, 23-95 °C of reaction temperature, 7:1-14:1 of liquid-solid ratio and 17.77-56.58 μm of average particle size. The results show that the leaching rate increases with increasing the sodium sulfite concentration, agitation speed, reaction temperature or liquid-solid ratio and the leaching rate decreases with increasing the particle size. The reaction temperature has the significant effects on the selenium leaching rate which increases from 21% to 67% with increasing temperature from 23 °C to 95 °C. The experimental data agree quite well with the Avrami model for leaching, with model parameter of 0.235 and apparent activation energy of 20.847 kJ/mol. © 2014 The Nonferrous Metals Society of China.
Zhu Y.C.,Northwestern Polytechnical University |
Zeng W.D.,Northwestern Polytechnical University |
Liu J.L.,Northwestern Polytechnical University |
Zhao Y.Q.,Northwest Institute for Nonferrous Metal Research |
And 2 more authors.
Materials and Design | Year: 2012
Isothermal compression tests of as-cast Ti-6A1-2Zr-2Sn-3Mo-1Cr-2Nb (TC21) titanium alloy are conducted in the deformation temperature ranging from 1000 to 1150°C with an interval of 50°C, strain rate ranging from 0.01 to 10.0s-1 and height reductions of 30%, 45%, 60% and 75% on a computer controlled Gleeble 3500 simulator. The true stress-strain curves under different deformation conditions are obtained. Based on the experimental data, the effects of deformation parameters on the hot deformation behavior of as-cast TC21 alloy were studied. The deformation mechanisms of the alloy in the whole regimes are predicted by the power dissipation efficiency and instability parameter and further investigated through the microstructure observation. It is found that at the height reductions of 30%, 45% and 60%, the softening of stress-strain curves at high strain rate (>1.0s-1) is mainly associated with flow localization, which is caused by local temperature rise, whereas at low strain rate, the softening is associated with dynamic recrystallization (DRX). However, the instability showed in flow localization occurs at low strain rate of 0.01s-1 when the height reduction reaches 75%. In addition, the effects of strain rate, deformation temperature and height reduction on microstructure evolution are discussed in detail, respectively. © 2011 Elsevier Ltd.
Wang B.,Northwest Institute for Nonferrous Metal Research
Xiyou Jinshu Cailiao Yu Gongcheng/Rare Metal Materials and Engineering | Year: 2014
Hot tube extrusion process of Inconel 690 alloy was investigated by simulation and experiments. The results show that temperature of the billet increases greatly with the extrusion speed increasing. The extrusion force first decreases and then increase. The extrusion force decreases linearly with the heating temperature increasing. For the situation of radial temperature gradient existing on the tube, it can be found that the initial inhomogeneous tube temperature distribution affects the alloy flow seriously during the hot tube extrusion process which leads to some defects on the surface. Based on the simulation results, the hot extrusion process is designed to obtain the qualified superalloy tube successfully. ©, 2015, Science Press. All right reserved.
Canyang L.,Northwest Institute for Nonferrous Metal Research
Proceedings - 2015 7th International Conference on Measuring Technology and Mechatronics Automation, ICMTMA 2015 | Year: 2015
Groundwater has an important influence to landslide stability, therefore, how to effectively drain off the groundwater from large-scale landslide have always been a hot research topic, this paper, first of all, summarizes conventional slope drainage measures and their respective serviceability, then carries out computational analysis, it puts forth drainage tunnel can effectively lower the water level and increase landslide safety factor, on the ground of detailed geological investigation and theoretical analysis, drainage tunnel was successfully applied to the treatment of some large-scale landslide, results showed that the drainage effects was much more better than expected, this effectively guaranteed landslide's stability and treatment effects, hence, drainage tunnel is a good way to descend water level. © 2015 IEEE.
Kent D.,University of Queensland |
Wang G.,University of Queensland |
Yu Z.,Northwest Institute for Nonferrous Metal Research |
Ma X.,Northwest Institute for Nonferrous Metal Research |
Dargusch M.,University of Queensland
Journal of the Mechanical Behavior of Biomedical Materials | Year: 2011
The strength of a biomedical β-type alloy, Ti-25Nb-3Zr-3Mo-2Sn, was enhanced through severe plastic deformation using a modified accumulative roll bonding technique. Incremental strength increases were observed after each cycle, while ductility initially fell but showed some recovery with further cycles. After 4 cycles there was a 70% improvement in the ultimate tensile strength to 1220 MPa, a two-fold increase in the 0.5% proof stress to 946 MPa and the ductility was 4.5%. The microstructure comprised of ultrafine grain β grains heavily elongated in the rolling direction with a fine dispersion of nanocrystalline α phase precipitates on the β grain boundaries. Shear bands formed in order to accommodate large plastic strains during processing and the grains within the bands were significantly finer than the surrounding matrix. © 2010 Elsevier Ltd.
Zhao Y.-Q.,Northwest Institute for Nonferrous Metal Research |
Ge P.,Northwest Institute for Nonferrous Metal Research
Hangkong Cailiao Xuebao/Journal of Aeronautical Materials | Year: 2014
Titanium alloys are widely used because of their excellent comprehensive properties. The research and development of new titanium alloys in recent 20 years in China, including high strength alloys, damage tolerance alloys, high temperature alloys, corrosion resistant alloys, alloys used for ship-building, low cost alloys, medical alloys and so on were reviewed. The research and development of titanium alloys in China changed from early imitation to independent research. The new titanium alloys invented in China are over 30 kinds. The important development trend of titanium is low cost, short technological process, near net shaping and so on.