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Exploration of the structure, properties, and anisotropy of (r, h)-TiAl2 under high pressure
Solid State Sciences ( IF 3.5 ) Pub Date : 2021-03-11 , DOI: 10.1016/j.solidstatesciences.2021.106580
Yang Xu , Yong Cao , Changyi Hu , Cong Zhang , Chang Tian , Sultan Alzoabi , Nathan Santos , Shenggang Zhou

In this study, we use the first principles calculation based on the density functional theory (DFT) to investigate the effects of high pressure on the structural, anisotropic, mechanical, and thermal properties and the phase stability of r-TiAl2 (HfGa2 type) and h-TiAl2 (ZrGa2 type). The calculation results of the formation enthalpy indicate that r-TiAl2 and h-TiAl2 remain stable under the 0–40 GPa. There is no phase transition, and the two phase structures are mechanically stable under the applied pressure. The Bulk modulus (B), Shear modulus (G), and Young's modulus (E) increase with increasing pressure from 0 to 40 GPa. The 3D surface structure of the elastic modulus and the universal elastic anisotropy index (AU) indicate that the elastic anisotropy of h-TiAl2 is higher than that of r-TiAl2. In addition, Sound velocity and Debye temperature are investigated from analysis of the elastic constants and moduli. Finally, the density of states and charge density difference are also discussed.



中文翻译:

高压下(r,h)-TiAl 2的结构,性质和各向异性的探索

在这项研究中,我们使用基于密度泛函理论(DFT)的第一性原理计算来研究高压对r-TiAl 2(HfGa 2型)的结构,各向异性,机械和热性能以及相稳定性的影响)和h-TiAl 2(ZrGa 2型)。生成焓的计算结果表明,r-TiAl 2和h-TiAl 2在0-40 GPa下保持稳定。没有相变,并且两相结构在施加的压力下机械稳定。体积模量(B),剪切模量(G)和杨氏模量(E))随着压力从0到40 GPa的增加而增加。弹性模量和通用弹性各向异性指数(A U)的3D表面结构表明,h-TiAl 2的弹性各向异性高于r-TiAl 2的弹性各向异性。另外,通过分析弹性常数和模量来研究声速和德拜温度。最后,还讨论了状态密度和电荷密度差。

更新日期:2021-03-16
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