The vacancy defects and oxygen atoms occupation effects on mechanical and electronic properties of Mo5Si3 silicides

• 作者: Jiaying Chen Xudong Zhang Linmei Yang Feng Wang
• 来源期刊: 理论物理通讯（英文版）
• 年，卷（期）: 2021,（4）
• 所属期刊栏目: CONDENSED MATTER THEORY
• 页码范围: 121-129
• 页数: 9页
• 语种: 英文

摘要

Improving brittle behavior and mechanical properties is still a big challenge for nigh-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 Mo5Si3.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 Mo5Si3 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 Mo5Si3.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 Mo5Si3.