Mg-Zn-Y合金中14H-LPSO相与W相的电子结构与弹性性能的第一性原理计算  

First-principles Calculations of Electronic Structures and Elastic Properties of 14H-LPSO and W Phases in Mg-Zn-Y Alloy

作　　者：徐志超[1] 冯中学[1] 史庆南[1] 杨应湘[2] XU Zhichao;FENG Zhongxue;SHI Qingnan;YANG Yingxiang(Faculty of Material Science and Engineering,Kunming University of Science and Technology,Kunming 650093;Key Laboratory of Advanced Materials of Yunnan Province,Kunming 650093)

机构地区：[1]昆明理工大学材料科学与工程学院,昆明650093 [2]云南省新材料制备与加工重点实验室,昆明650093

出　　处：《材料导报》2018年第6期1026-1031,共6页Materials Reports

基　　金：云南省科技厅青年基金(2016FD033);省级人培项目(KKSY201351055);教育部博士点基金(20135314110003);校重点基金(KKZ1201451001)

摘　　要：运用密度泛函理论的第一性原理平面波赝势方法计算了14H-LPSO相和Mg_3Y_2Zn_3(W相)的能带、态密度、电子结构及弹性常数,计算的晶格参数与实验值相吻合。能带结构和态密度分析计算结果显示,14H-LPSO相成键能量范围主要在-8~3eV之间,W相的成键能量范围主要在-8~0.5eV之间。这表明LPSO相成键峰主要来自Mg3s、Zn4s、Y5s和4p轨道,W相的成键峰主要来自Mg3s、Zn3p和Y4d轨道。14H-LPSO相的(0001)面的电荷密度分析表明,Zn原子和Mg原子之间的电子云重叠较强,两者形成了较强的共价键;Zn原子和Y原子之间的电子云重叠较弱,形成较弱的共价键;W相的(011)面的电荷密度分析表明Zn原子和Y原子之间的电子云重叠较强,两者形成了较强的共价键。通过计算14H-LPSO相与W相的弹性常数,推导了体积模量、剪切模量、杨氏模量、泊松比、弹性各向异性系数的计算式。将两者与Mg基体进行比较,结果表明,三者的塑性关系为Mg基体>14H-LPSO相>W相,其中W相的硬度最大。The density of states,electronic structure and elastic constants of 14H-LPSO and W phase in Mg-Zn-Y alloy were analyzed by means of first-principles calculations from CASTEP program based on density functional theory(DFT).The calculated lattice parameters were consistent with the experimental and literature values.The calculated band structure and density of states demonstrates that the bonding of the 14-LPSO occur mainly among the valence electrons of Mg3s,Zn4s,Y5s,Y4p orbits,and the energy is in a range from-8 eV to 3 eV.Similarly,the bonding of the Mg 3Y 2Zn 3 occur mainly among the valence electrons of Mg3s,Zn3p,Y4d orbits,and the energy is in a range from-8 eV to 0.5 eV.In addition,the charge densities respectively on(011)plane of Mg 3Y 2Zn 3 phase and(0001)plane of 14H phase were analyzed,and the results indicate that the Zn-Y band exhibits covalent features,the covalent bonding of phase is stronger than that of 14-LPSO phase.According to the calculated elastic canstants,the bulk moduli,shear moduli,Yong’s moduli,Poisson’s ratio value and elastic anisotropy were derived.Furthermore,comparing the 14H-LPSO,W phase with Mg,the plasticity of the three phase is Mg>14H-LPSO>W.The W phase has the biggest hardness among three phases.

关 键 词：14H-LPSO Mg3Y2Zn3 第一性原理 态密度 弹性常数 力学性能 

分 类 号：TG146.22[一般工业技术—材料科学与工程]