The microstructure and phase composition of Sm-Fe alloy with 24% Sm in different crystallization stages were determined by means of XRD,SEM and DSC.The effects of temperature and time on the crystallization of amorphous Sm-Fe alloy were studied.The results show that even if the rapid quenching speed reaches 35 m/s and the cooling rate reaches 1.03×10^6 K/s,only 10%~20% amorphous content can be obtained in rapidly quenched ribbons of Sm-Fe alloy.After the rapidly quenched ribbons are ball-milled for 2.5 h,the main phase Sm2Fe17 has become complete amorphous,and only a small amount of α-Fe phase exists in the alloy.The optimal crystallization temperature and time of the amorphous powder from 2.5 h ball milling of Sm-Fe alloy ribbons are 700 ℃ and 20 min,respectively.

The effect of cooling rate after solution on microstructure and mechanical properties of a new type of short-time high-temperature titanium alloy hot-rolled sheet was studied.The results show that the alloy has different phase products after high-temperature solid solution near the beta zone and cooling in diffe-rent ways.The α and β phases are obtained by air cooling,while α′ and α″ phases are produced by oil cooling and water cooling.With the increase of cooling rate,the strength of the alloy increases,while its plasticity decreases.The titanium alloy can obtain excellent comprehensive mechanical properties by oil cooling after solution treatment,and its room-temperature tensile strength and elongation exceed 1 150 MPa and 8%,respectively.

The CrxNbTiZr high entropy alloys of mixed strengthening effects were designed according to the phase formation criterion.The effect of chromium on the microstructure and mechanical properties of the CrxNbTiZr high entropy alloys was researched by X-ray diffractometer,scanning electron microscope and universal mechanical testing machine.The results show that the CrxNbTiZr high entropy alloys are composed of BCC phase and some Cr2M(M=Nb,Ti,Zr) Laves-phase intermetallic compounds.The alloys present typical dendritic morphology,in which the second phase discontinuously precipitates.By the solid solution strengthening of Cr and the second phase strengthening of Laves phase,the Cr1.0 alloy possesses the yield strength up to 1 401 MPa,the compressive strength up to 1 677 MPa and the fracture strain down to 13.30%.The fracture morphology analysis shows that the series of alloys have the mixed fracture cha-racteristics of ductility and brittleness.

The research progress of spent LiCoO2 material regeneration at home and abroad in recent years is reviewed.Based on the difference in regeneration process,the regeneration process of spent LiCoO2 material is divided into direct regeneration method and indirect regeneration method,and the advantages and disadvantages of each method are compared.It is pointed out that the future development trend of the spent LiCoO2 material regeneration method is to develop green,efficient and low-cost recycling process.

High-cycle fatigue tests of the isostatically pressed beryllium material were carried out using the pull-pull loading method.The S-N curve was drawn according to the test data to obtain its fatigue limit,and the fatigue fracture morphology was observed using a scanning electron microscope.The results show that fatigue limit of the isostatically pressed beryllium material is 385 MPa,corresponding to the specified fatigue life of 10~7 times.Fatigue cracks initiate at the edge of the beryllium sample,and the cracks cross the grain boundary and grow up with microcracks in the adjacent grains.The beryllium sample instantaneously cleaves and fractures,forming the fracture morphology mainly consisting of fatigue sources and radiation zones.The size of the fatigue source increases with the decrease of the maximum cyclic stress.

Taking p-type Bi0.3Sb1.7Te3 alloy as the research object,the effect of In doping on its electron and phonon transport properties was investigated.The results show that with the increase of In content,Seebeck coefficient increases and the electrical conductivity decreases.When the In content is 0.025,the sample has the optimal power factor of 37.02 μW/(K^2·cm).Furthermore,the point defect concentration and lattice distortion degree of the material increase with In doping,which leads to the enhanced scattering of phonons and then the decreased thermal conductivity of the material.Consequently,the sample with In content of 0.050 has the optimal ZT of 1.11 at 401 K.This work provides an effective method to improve the thermoelectric properties of p-type Bi0.3Sb1.7Te3 alloy,and increases the applied potential of thermoelectric materials.

WC-6 Co cemented carbides with different Mo contents were fabricated by SPS.The phase composition,microstructure and mechanical properties of the alloy were analyzed by XRD,SEM and frictional wear machine.The electrochemical corrosion behavior of the alloy was analyzed by potentiodynamic polarization curves.And thus effects of Mo on the microstructure,hardness,wear resistance and corrosion resistance of the alloy were studied.The results show that Mo addition can effectively suppress the growth of WC grains and increase the hardness of the alloy.However,with the increase of Mo content,the relative density of the alloy gradually decreases,its hardness increases at first and then decreases,and its wear resistance also decreases.The corrosion resistance of the alloy in acid solution can be effectively enhanced by Mo addition.The alloy is more susceptible to corrosion by hydrochloric acid,but SO4^2- is more aggressive than Cl^- to corrode the alloy.The corrosion current density of the alloy in sulfuric acid is greater,and the corrosion rate is faster.

YT5 cemented carbide was used as the research object,and the alloy sample was prepared by wet grinding and sintering with 0~0.15% stearic acid as the surfactant.The effect of surfactant content on microstructure and properties of YT5 cemented carbide was studied by microstructure observation,particle size analysis and physical and mechanical property testing.The results show that with the increase of surfactant content,the average grain size of WC and(Ti,W)C phases decreases,and the coercivity and hardness of the alloy slightly increases.The coercivity increases by 0.2% for per 0.04% increase of surfactant addition.A small amount of surfactant has little effect on the density,bending strength,cobalt magnetism and porosity of YT5 alloy.

我国有着13亿人口,任何一个微不足道的数字乘以13亿都将是一个天文数字。研究资料显示:如果全国平均每人每年减少粮食浪费0.5千克,每年可节约能源24.1万吨标准煤,减排二氧化碳61.2万吨;如果全国1 248万辆私人轿车每月少开一天,每年可节油5.54亿升,减排二氧化碳122万吨。

In order to efficiently and rationally develop Zhijin phosphorite and optimize the rare earth enrichment process,the solvent extraction method was used to remove iron from 4-stage hydrochloric acid leaching solution of Zhijin phosphorite,and then the rare earth elements in the extract solution were enriched by the solvent extraction method.The effects of O/A,extraction time,P204 concentration and extraction times on the extraction rate of rare earth were studied.The results show that when 15 mL N235+(1~5)mL isooctanol+(34~30)mL sulfonated kerosene is used as the iron extraction agent,the content of isooctanol and sulfonated kerosene has little effect on the iron extraction effect,and the iron extraction rate is close to 100%.The optimized extraction conditions of rare earth are O/A of 3∶1,P204 concentration of 1.5 mol/L and extraction time of 15 min.Under the optimized conditions,the extraction rate of rare earth reaches 82.24%after four times of extraction.