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arXiv 1111.1618cond-mat.mtrl-sci
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B2-AlRE(RE =Y,Tb,Pr,Nd,Dy)金属间化合物有限温度弹性性质的第一性原理计算

First-principles calculations on finite temperature elastic properties of B2-AlRE (RE=Y, Tb, Pr, Nd, Dy) intermetallics

Rui Wang, Shaofeng Wang, Xiaozhi Wu

摘要:

本文从第一性原理出发,研究了具有B_2型结构的AlRE(RE=Y,Tb,Pr,Nd,Dy)的有限温度弹性性质。采用基于密度泛函微扰理论的准谐波方法,得到了声子自由能和热膨胀。采用第一性原理总能量法,由能量-应变函数得到了与体积有关的静态弹性常数。我们的预测结果和超声实验数据的基准材料铝之间的比较提供了很好的协议。在T = 0 K时,我们计算的AlRE(RE=Y,Tb,Pr,Nd,Dy)金属间化合物的晶格平衡体积和弹性模量与前人的理论结果符合得很好。温度依赖性弹性常数表现出随温度的正常行为,即,在较高温度下下降并接近线性,在零温度附近为零斜率。此外,还讨论了各向异性比和声速随温度的变化。

英文摘要:

We have investigated the finite temperature elastic properties of AlRE (RE=Y, Tb, Pr, Nd, Dy) with B2-type structures from first principles. The phonon free energy and thermal expansion is obtained from the quasiharmonic approach based on density-functional perturbation theory. The static volume-dependent elastic constants are obtained from energy-strain functions by using the first-principles total-energy method. The comparison between our predicted results and the ultrasonic experimental data for a benchmark material Al provides excellent agreements. At T = 0K, our calculated values of lattice equilibrium volume and elastic moduli of our calculated AlRE (RE=Y, Tb, Pr, Nd, Dy) intermetallics agree well with the previous theoretical results. The temperature dependent elastic constants exhibit a normal behavior with temperature, i.e., decrease and approach linearity at higher temperature and zero slope around zero temperature. Furthermore, the anisotropy ratio and sound velocities as a function of temperature has also been discussed.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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