Tix-Nb1-x合金结构及弹性性质的第一性原理研究

本文基于密度泛函理论的第一性原理计算方法详细地计算了高温高压下不同铌含量对Tix-Nb1-x (x=0， 025, 05, 075，1)二元合金的能量和结构的影响。结果表明，零温零压下不同铌含量下的三种稳定的合金组成结构分别为六角密堆结构Nb025Ti075，体心立方结构 Nb05Ti05和体心立方结构Nb075Ti025，所得的稳定的合金结构晶格参数与相关的实验值和理论值符合的很好。这样, 分别计算了在压强60GPa范围内的稳定的合金结构的弹性性质和弹性模量。

First-principles calculations of structural and elastic properties of Tix-Nb1-x alloys

The structural properties of Tix-Nb1-x (x=0.25, 0.5, 0.75) alloy systems under high pressure and temperature are investigated by first-principles calculations. The calculated lattice parameters of several Tix-Nb1-x alloy systems are consistent with the pre-existing experimental data and other theoretical data. Through the fitting of the energy-volume (E-V) curve, we draw a conclusion that the Nb0.75Ti0.25 and Nb0.5Ti0.5 are energetically favored to be in body-center cubic structures, but Nb0.25Ti0.75 alloys to be in hexagonal cubic structure. The elastic properties and elastic modulus of the stable Nb0.75Ti0.25, Ti0.5Nb0.5 and Ti0.75Nb0.25 alloy structures are also computed.