Tensile tests were conducted on powder metallurgy Be-Al alloy at -100～500 ℃ ,and the effect of temperature on its mechanical properties was analyzed. Its fracture morphologies at different tempera- ture were obtained using scanning electron microscope. The results show that both tensile strength and yield strength decrease with improved temperature, but elongation firstly rises and then falls with improved temperature. The fracture mechanism of Be-Al alloy varies with improved temperature. At low tempera- ture, it is characterized by the mixed fracture of cleavage fracture of beryllium phase and ductile fracture of aluminum phase. With the temperature increasing, cracking of Be/Al interface and ductile fracture of alu- minum phase become main fracture morphologies. The inner stress field distribution of Be-Al alloy in high and low temperature tensile process is simulated with ABAQUS finite element software to reveal the me- chanical mechanism of transition of tensile fracture mode of Be-Al alloy at high temperature.

De-β-1ayered gradient cemented carbide was prepared by micro-pressure nitrification and vacuum denitrification sintering with nitrogen-free raw material. The microstructure and element distribution of al- loy samples at different sintering steps were analyzed by SEM, EDS and EPMA techniques, their micro- structure evolution rules during sintering were investigated,and the formation mechanisms of cubic carbide free layer and Co-rich layer were summarized. The results indicate that TiC phase in the cemented carbide is nitrided to Ti（C,N） phase during micro-pressure nitrification. And then the dissolution of Ti（C,N） into the liquid phase and the N-Ti coupling diffusion result in the formation of cubic carbide free layer during denitrification sintering. The combined action of Co vacancy diffusion and liquid migration is responsible for the formation of Co-rich layer. Liquid migration during cooling results in the difference of Co content in dif- ferent regions of Co-rich layer.

2016年12月8日上午,户外寒风阵阵,室内春意融融,中铝国际工程股份有限公司在北京总部隆重举行了＂工程用铝＂系列产品合作签字仪式,与国内包括地方政府、大型央企和知名民企在内的多家合作伙伴,成功签订了11项铝材产品合作协议及销售合同,涉及铝通信塔、铝天桥、铝模板、铝质集成房屋、建筑铝爬架、手机壳合金、汽车零部件、铝防洪墙等几十项产品。签字仪式现场布置得庄重而朴素,

The four light rare earth elements of La, Ce, Pr and Nd were extracted by fuzzy linkage extraction technology from Baotou mixed rare earth ore. Compared with the traditional process, fuzzy linkage extraction technology is a separation process for light rare earth with obvious energy conservation and emission reduction effects. The new technology has the advantages of less investment in infrastructure and good extraction separation efficiency. Its acid and alkali consumption can be reduced by about 20 %,and its unit discharge of waste water is only 79.4% of that of the traditional technology.

Investigation is made on the amount of the residual elements by ICP-AES and ICP-MS during va- nadium extraction from direct acid leaching solution of carbonaceous shale vanadium ore. During alkali addition for impurity removal,vanadium retention rate is high at pH of 2.8 and 12.2,and element retention rate-pH curves are divided into four groups： U-type curves, descending curves, ascending curves and horizontal curves. During oxidation,four kinds of oxidants were added into the solution with the pH of 2.8 and 12.2. In terms of oxidation effect and production cost,the use of Na2S2O8 with pH of 2.8 can result in optimal oxidization effect. Extraction-stripping cannot remove Na impurity of the highest content, but it can greatly increase the content of P impurity instead. The necessity of extraction-stripping is to be further studied

Research is done on the catalytic oxidation and hydrochloric acid leaching of nickel and cobalt from nickel concentrate under normal pressure with oxygen and copper chloride as oxidizing agent and catalytic agent, respectively. The influences were investigated of leaching temperature, leaching acidity, oxidation-reduction potential, particle size of nickel concentrate and catalytic agent concentration on nickel and cobalt leaching rate. The optimal technical parameters of hydrochloric acid catalytic oxidation leaching were determined by experimental study. The leaching rate of nickel and cobalt can reach 98. 16% and 93.32% respectively under the conditions as follows：leaching duration of 180 min,leaching temperature of 90℃ ,final potential of leaching solution of 520 mV, nickel concentrate particle size less than 0. 075 mm, stirring speed of 600 r/min,liquid-solid ratio of 4 ： 1,leaching acidity of 2 mol/L,Cu2＋ concentration of 25 g/L, NaCl concentration of 100 g/L,and oxygen flow rate of 0.5-0.6 L/min.

Porous tungsten blank with continuous porosity gradient was prepared via oxidation-gasification reaction between water vapor and W powder particles. The effects were investigated of W powder granularity composition,reaction temperature and time on porosity gradient of the tungsten blank. The microstructure of the sample was observed by metallographic microscope, and the volume fraction of its pores was measured by image analysis software. The results show that porous tungsten blank with continuous porosity gradient can be obtained with oxidation-gasification method, and its porosity decreases gradually from surface to core. Fine tungsten powder is very beneficial to pore construction, and the tungsten blank containing more fine powder has higher porosity and porosity gradient. Higher reaction temperature also results in higher porosity and porosity gradient of the tungsten blank. The longer the reaction time, the higher the porosity and the larger the porosity gradient area of the tungsten blank. Furthermore, surface pores have larger size than core pores of the sample.

Nanocrystalline （Ti,W）（B,C,N） powders were prepared by precursor plus carbothermal reduction with metatitanic acid,ammonium metatungstate,xylose and boracic acid as the materials. Phase composition and microstructure of the products were characterized by SEM and XRD. The effects of synthesis temperature and holding time on reaction products were discussed. The results show that both synthesis temperature and holding time have obvious effects on the synthesis of （Ti,W）（B,C,N） powders. With the increase of synthesis temperature and holding time, synthetic powder grains significantly grow up. Nano- crystalline （Ti,W）（B,C,N） powders with grain size of 21.3 nm are successfully prepared at 1 200 ℃ for 2 h. Compared with the traditional method of ordinary ball milling plus carbothermal reduction, the method of precursor plus carbothermal reduction can significantly reduce synthesis temperature with an advantage of low cost of raw materials.

Al2 O3-doped W powder was prepared by sol-gel, azeotropic distillation and hydrothermal synthesis to produce W-Al2 O3 composite powder by calcination and two-step H2 reduction. Based on XRD analysis and SEM observation, stable monoclinic WOa and metastable hexagonal WO3 were obtained by calcination of Al2 O3-doped W powder prepared with the above-mentioned three methods. The morphology of the powder prepared by hydrothermal synthesis is regular, uniform and spherical. WO3 is reduced to low-valence WO2 and unsaturated-valence WO3-x by the primary H2 reduction,and fine W-Al2 O3 composite powder is obtained by the secondary H2 reduction. Compared with the other two methods, sol-gel method has more obvious refinement effect and it can prepare W-Al2O3 composite powder with nanoscale particle size, since Al2 O3 coated on the surfaces of W particles inhibits the deposition of tungsten atom during subsequent reduction.

Phase stability and electronic properties of pure Cr2 N and Cr2 N doped with transition metals （W, Mo, Nb, Fe, Ni） were investigated by the first-principles calculation based on the density functional theory. Stable Cr23MN12 （M= W, Mo, Nb, Fe, Ni） composite nitride can be formed by replacing Cr with W, Mo, Nb, Fe and Ni in Cr2 N supercells, based on the formation enthalpy and cohesive energy. Among the doping elements,Nb is most easily doped in Cr2 N to form Cr23 NbN12 composite nitride. Cr23 WN12 and Cr23 MoN12 are more stable than pure Cr24N12, due to orbit hybridization of W-5d, Mo-4d and N-2p. Compared with pure Cr2 N, Cr23 FEN12 and Cr23 NiNe2 have reduced stability and enhanced electrochemical activity, owing to the charge transfer from N to Fe and Ni.