高压下Ni_3Al热力学性质的第一性原理研究  

Thermodynamic properties of Ni_3Al under pressure via first-principles calculations

作　　者：李强[1] 黄多辉[1] 曹启龙[1] 杨俊升[1] 王藩侯[1] 

机构地区：[1]宜宾学院计算物理四川省高等学校重点实验室,宜宾644000

出　　处：《原子与分子物理学报》2013年第5期798-803,共6页Journal of Atomic and Molecular Physics

基　　金：国家自然科学基金(61275203);冲击波物理与爆轰物理国防科技重点实验室基金;四川省教育厅基金(09ZC048)

摘　　要：运用第一性原理方法结合准谐Debye-Grüneisen模型研究了高压下Ni3Al的热力学性质,拟合了Ni3Al的状态方程,计算了不同压强下Ni3Al的弹性模量及吉布斯自由能等热力学性质随温度的变化关系.计算结果表明:采用七阶Birch-Murnaghan方程拟合的晶格常数与实验测量结果吻合较好;零压下弹性模量、吉布斯自由能、焓、熵、热容和体膨胀系数随温度的变化与实验值符合较好;在特定压强下,Ni3Al的弹性模量和吉布斯自由能随温度升高而减小,焓、熵随温度升高而增加;预测的德拜温度约为500K,与实验值符合较好.Within the framework of the quasiharmonic Debye-Grtineisen approximation, the equation of state and thermodynamics properties of Ni3Al under pressure have been studied using the first-principles projector-augmented wave method. The results reveal that the lattice constants from the seven-order Birch-Murnaghan equation are in agreement with the experimental data. The calculated Gibbs free ener- gy, enthalpy, entropy, heat capacity and volume thermal expansion coefficient of Ni3 A1 at 0 GPa as a function of temperature are consistent well with the experimental data. At different pressures, the bulk modulus and Gibbs free energy decrease but the enthalpy and entropy increase with the increasing of temperature. The estimated Debye temperature of Ni3Al from heat capacity at constant volume is 500 K. The value is in agreement with the available measured values.

关 键 词：第一性原理 Debye-Grüneisen模型 NI3AL 热力学 

分 类 号：O52[理学—高压高温物理]