Measurement of transient Raman spectrum on gas-gun loading platform and its application in liquid silane

Combining a low temperature liquidizing system with a transient Raman spectroscopy, a new experimental technique is established for the first time on a two-stage light-gas gun, and it is employed to study shock-compressed fluid silane. With this experimental technique, we first obtain a Raman peak shift relating to the Si–H stretching vibration mode of molecular liquid silane under shock loading conditions. The Raman peak of 2184 cm~(-1) at an initial state of 0 GPa and 85 K moves to 2223.4 cm~(-1) at a shocked state of 10.5 GPa and 950 K, and its full width of half maximum broadens from 33 cm~(-1) to 118 cm~(-1). The shocked temperature, calculated by the thermodynamic equation of state, is well consistent with that estimated by the Doppler broadening function.     

孔隙率对铌硅粉末混合物冲击反应的影响

借助二级轻气炮加载平台和飞片撞击技术,在高冲击速度下实现不同初始孔隙率铌硅粉末混合物的冲击回收。对回收产物进行表征分析并探讨高冲击速度下孔隙率对铌硅粉末冲击化学反应的影响,实验结果表明:低孔隙率(10%)铌硅粉末混合物几乎不发生反应;20%孔隙率铌硅粉末发生不完全化学反应并生成了NbSi2;高孔隙率(35%)样品在相同冲击速度(飞片速度约为2.35 km/s)下发生完全反应获得单组分Nb5Si3。在高孔隙率的粉末混合物中,孔隙崩塌产生的高温是导致铌硅粉末反应物发生完全反应的主要原因。     

Theoretics-directed effect of copper or aluminum content on the ductility characteristics of Al-based(Al_3Ti,AlTi,AlCu,AlTiCu_2)intermetallic compounds

First-principle simulations have been applied to investigate the effect of copper(Cu) or aluminum(Al) content on the ductility of Al_3Ti,AlTi,AlCu,and AlTiCu_2 alloys.The mechanical stable and elastic properties of Al-based intermetallic compounds are researched by density functional theory with the generalized gradient approximation(DFT-GGA).The calculated lattice constants are in conformity with the previous experimental and theoretical data.The deduced elastic constants show that the investigated Al_3Ti,AlTi,AlCu,and AlTiCu_2 structures are mechanically stable.Shear modulus,Young's modulus,Poisson's ratio,and the ratio B/G have also been figured out by using reckoned elastic constants.A further analysis of Young's modulus and Poisson's ratio reveals that the third added element copper content has significant effects on the Al-Ti-based ICs ductile character.