新型超硬材料AlMgB_(14)高温高压物态方程和力学性质的第一性原理计算  

Equation of state and mechanical properties of AlMgB_(14) under high temperature and pressure:a first-principles study

作　　者：周梦 景素华 王彬彬 ZHOU Meng;JING Su-Hua;WANG Bin-Bin(Department of Basics,Officers College of PAP,Chengdu 610213,China;Physics and Space Science College,China West Normal University,Nanchong 637002,China)

机构地区：[1]武警警官学院基础部,成都610213 [2]西华师范大学物理与空间科学学院,南充637002

出　　处：《原子与分子物理学报》2021年第3期106-115,共10页Journal of Atomic and Molecular Physics

基　　金：西华师范大学基本科研业务费资金(412775)。

摘　　要：新型三元超硬复合材料AlMgB_(14)由于具有硬度高、密度低、热稳定性好、导电性能好且制作成本低等一系列优良特性,而成为超硬材料领域的研究热点.本文基于密度泛函理论的第一性原理算法,运用计算机模拟技术,模拟实际实验中难以达到的高温和高压条件,结合Kohn-Sham方程的自洽求解计算新型超硬材料AlMgB_(14)在高温高压下的力学性质、物态方程.从而对比获得其物理化学性质与高压弹性常数,并讨论其背后的物理本质.本文首先对AlMgB_(14)进行结构优化;其次,计算在不同原胞体积下所对应的晶格总能量,获得了AlMgB_(14)的状态方程参数、热力学性质及其随温度和压力的变化关系.同时也研究了常压及加压时,AlMgB_(14)晶体的弹性性质的特点及变化情况.研究结果不仅构建了微观结构AlMgB_(14)与其宏观物理特性之间的桥梁,同时为其材料的工程应用和基础理论研究提供良好的帮助,而且本论文采用的理论计算方法还可以应用到其它材料的物态方程研究中.The new ternary Super-hard material AlMgB_(14) has become a research focus in the field of Superhard materials due to its excellent properties of high hardness,low density,good thermal stability,good electrical conductivity and low production cost. Based on the first principles algorithm of density functional theory and the self-consistent solution of Kohn-Sham equation,the mechanical and state equation of AlMgB_(14) under high temperature and high pressure were calculated. The physico-chemical properties and the high pressure elastic constants were compared and discussed. At the same time,this thesis uses computer simulation technology to simulate the high temperature and high pressure conditions difficult to achieve in practical experiments. Firstly,AlMgB_(14) was optimized. Secondly,the total lattice energies of the AlMgB_(14) were calculated under different cell volumes. The equation of state,the thermodynamic properties and the relationship between temperature and pressure were obtained. The results obtained by the simulation of AlMgB_(14) are in good agreement with some of the existing experimental results. The results not only build a bridge between the microstructure AlMgB_(14) and its macroscopic physical properties,but also provide good help for the engineering application and basic theory research of the material. Moreover,the theoretical calculation method used in this thesis can also be applied to the research on the equation of state for other materials.

关 键 词：超硬材料 AlMgB_(14) 第一性原理 高压性质 

分 类 号：O52[理学—高压高温物理]