摘要
基于密度泛函理论的第一性原理计算获得了α-Ti2Zr的晶体结构、弹性常数、德拜温度和电子分布情况,研究了它们与压力的关系.计算得到的晶体结构参数与实验值一致.运用有限应变方法计算得到了α-Ti2Zr的体积模量B、剪切模量G、杨氏模量E和泊松比σ.B和E的零压值分别为101.2和35.6GPa.G/B的值较小,并且随着压力的增加而减小,表明α-Ti2Zr具有优异的延展性.基于弹性常数得到平均声速,从而获得了德拜温度Θ=321.7K.通过解Christoffel方程获得的压缩波和剪切波数据揭示α-Ti2Zr具有较强的各向异性.此外,压力诱导电子从s轨道到d轨道的转移说明在一定压力下α-Ti2Zr将转变为β相.
The structure, elastic constant, Debey temperature and electron distribution of α-Ti2Zr under high pressure are presented by using first-principles pseudopotential method based on density functional theory in this paper. The calculated structural parameters at zero pressure are in agreement with experimental values. The elastic constants and their pressure dependence are calculated using the static finite strain technique. We obtain the bulk modulus, Young’s modulus and Poisson’s ratio for α-Ti2Zr. The G and B at zero pressure are 101.2 and 35.6 GPa, respectively. The G/B value is relatively small and decreases with pressure increasing, showing that the α-Ti2Zr is rather ductile. The Debye temperature Θ=321.7 K is obtained by the average sound velocity based on elastic constants. We investigate anisotropies of the compressional wave and two shear waves. The acoustic velocities are obtained from elastic constants by solving Christoffel equation. The results indicate the strong anisotropy for α-Ti2Zr. Moreover, the pressure dependence of s→d electron transfer indicates that β-Ti2Zr will occur under high pressure.
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2013年第4期384-389,共6页
Acta Physica Sinica
基金
国家重点基础研究发展计划(批准号:2010CB731600)
国家国防科工局空间碎片专项(批准号:KJSP06209
KJSP06210)资助的课题~~
关键词
第一性原理
α-Ti2Zr
物性
高压
first-principles, a-Ti2Zr, physical properties, high-pressure
