Prediction of Pressure-Induced Structural Transition and Mechanical Properties of Mg Y from First-Principles Calculations  

作　　者：濮春英 荀显超 宋海珍 张飞武 卢志文 周大伟 

机构地区：[1]College of Physics and Electronic Engineering,Nanyang Normal University [2]Basic Department,Aviation University of Air Force [3]State Key Laboratory of Ore Deposit Geochemistry,Institute of Geochemistry,Chinese Academy of Sciences [4]Nanochemistry Research Institute,Curtin University

出　　处：《Communications in Theoretical Physics》2016年第1期92-98,共7页理论物理通讯（英文版）

基　　金：Supported by the Henan Joint Funds of the National Natural Science Foundation of China under Grant Nos.U1304612,U1404608;the National Natural Science Foundation of China under Grant Nos.51501093,51374132;the Special Fund of the Theoretical Physics of China under Grant No.11247222;Postdoctoral Science Foundation of China under Grant No.2015M581767;Young Core Instructor Foundation of Henan Province under Grant No.2015GGJS-122

摘　　要：Using the particle swarm optimization algorithm on crystal structure prediction,we first predict that Mg Y alloy undergoes a first-order phase transition from Cs Cl phase to P4/NMM phase at about 55 GPa with a small volume collapse of 2.63%.The dynamical stability of P4/NMM phase at 55 GPa is evaluated by the phonon spectrum calculation and the electronic structure is discussed.The elastic constants are calculated,after which the bulk moduli,shear moduli,Young's modui,and Debye temperature are derived.The brittleness/ductile behavior,and anisotropy of two phases under pressure are discussed in details.Our results show that external pressure can change the brittle behavior to ductile at10 GPa for Cs Cl phase and improve the ductility of Mg Y alloy.As pressure increases,the elastic anisotropy in shear of Cs Cl phase decreases,while that of P4/NMM phase remains nearly constant.The elastic anisotropic constructions of the directional dependences of reciprocals of bulk modulus and Young's modulus are also calculated and discussed.

关 键 词：high pressure phase transition first-principles calculations mechanical properties 

分 类 号：O469[理学—凝聚态物理]