压力对六角密堆结构金属锂弹性的影响

陈长波; 崔田; 刘志明; 邹广田; 韦孟伏; 陈长安

doi:10.11858/gywlxb.2005.04.008

压力对六角密堆结构金属锂弹性的影响

doi: 10.11858/gywlxb.2005.04.008

1.
吉林大学超硬材料国家重点实验室，吉林长春 130012；
2.
中国工程物理研究院，四川绵阳 621900

详细信息

通讯作者:
崔田

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出版历程
- 收稿日期: 2004-10-11
- 修回日期: 2005-09-01
- 发布日期: 2005-12-05

Pressure Effects on the Elastic Properties of the hcp Lithuim

1.
National Laboratory of Superhard Materials, Jilin University, Changchun 130023, China;
2.
China Academy of Engineering Physics, Mianyang 621900, China

More Information

Corresponding author: CUI Tian

摘要

摘要: 采用密度泛涵理论第一原理赝势方法，利用应力和应变的关系计算了压力下六角密堆结构金属锂的弹性常数。计算结果显示，C12、C13随着压力的增加而线性增加，而压力对C44和C66的影响并不大。在各个压力点C33值都要比C11的值大，表明金属锂在z方向的硬度要比x、y方向的硬度大。还发现在理论预测的结构相变区域，C11和C33有一个跳跃。通过对压缩波各向异性参数p和剪切波各向异性参数s1、s2的计算发现，零压下p＝1，并且高压下p值也接近1，表明压缩时金属锂表现出各向同性。s1、s2值远离1，并且随着压力的增加这种远离趋势不断增强，表现很强的剪切弹性各向异性。还讨论了压力对Cauchy关系和相对弹性常数的影响。
- 第一性原理 /
- 弹性常数 /
- 压力效应 /
- 金属锂 /
- 弹性各向异性
Abstract: The elastic constants of bulk lithium with hexagonal close-packed (hcp) structure under high pressures have been calculated, by using Density Functional Theory and the relationship between stress and strain. From our results, C12 and C13 increase linearly with pressures, but pressure effects on C44 and C66 are not obvious. At each pressure, C33 is bigger than C11, indicating rigidity of lithium in z direction is harder than that in x, y direction. It has been found that C11 and C33 have step-like changes in the phase transition zone. The results of the compressional wave anisotropy (p) show that p is equal to 1 at zero pressure and still near 1 under high pressure, meaning hcp lithium have the compressional elastic isotropy. The shear wave anisotropy (s1, s2) are away from 1 and this tendency increases with the increasing of pressure, showing the shear elastic anisotropy. Pressure effects on the Cauchy relations and the normalized elastic constants of hcp lithium are also discussed in this paper.
- first principles /
- the elastic constants /
- pressure effects /
- lithium /
- elastic anisotropy

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