The vacancy defects and oxygen atoms occupation effects on mechanical and electronic properties of Mo_(5)Si_(3) silicides  

作　　者：Jiaying Chen Xudong Zhang Linmei Yang Feng Wang 

机构地区：[1]School of Science,Shenyang University of Technology,Shenyang 110870,China [2]School of Materials Science and Engineering,Shenyang University of Technology,Shenyang 110870,China

出　　处：《Communications in Theoretical Physics》2021年第4期121-129,共9页理论物理通讯（英文版）

基　　金：supported by grants from the Province Nature Science Foundation of Liaoning Province(Grant No.2019JH/30100019)。

摘　　要：Improving brittle behavior and mechanical properties is still a big challenge for high-temperature structural materials.By means of first-principles calculations,in this paper,we systematically investigate the effect of vacancy and oxygen occupation on the elastic properties and brittle-or-ductile behavior on Mo_(5)Si_(3).Four vacancies(Si_(-Va1),Si_(-Va2),Mo_(-Va1),Mo_(-Va2))and oxygen occupation models(O_(Mo1),O_(Mo2),O_(-Si1),O_(-Si2))are selected for research.It is found that Mo_(-Va2) vacancy has the stronger structural stability in the ground state in comparison with other vacancies.Besides,the deformation resistance and hardness of the parent Mo_(5)Si_(3) are weakened due to the introduction of different vacancy defects and oxygen occupation.The ratio of B/G indicates that oxygen atoms occupation and vacancy defects result in brittle-to-ductile transition for Mo_(5)Si_(3).These vacancies and the oxygen atoms occupation change the localized hybridization between Mo-Si and Mo-Mo atoms.The weaker O-Mo bond is a contributing factor for the excellent ductile behavior in the O_(-Si2) model for Mo_(5)Si_(3).

关 键 词：vacancy defects oxygen atoms occupation mechanical properties ductile behavior electronic structure 

分 类 号：TQ136.12[化学工程—无机化工]