期刊
ACTA MATERIALIA
卷 145, 期 -, 页码 470-476出版社
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.actamat.2017.12.017
关键词
MoSi2; Embrittlement; Getter; Oxygen; DFT
资金
- Vannevar Bush Faculty Fellowship program - Basic Research Office of the Assistant secretary of Defense for Research and Engineering
- Office of Naval Research [N00014-16-1-2569]
- National Science Foundation [ACI-1053575]
MoSi2 is an important intermetallic with excellent oxidation resistance at high temperatures above 1000 degrees C. However, its application at lower temperatures is limited by oxygen embrittlement, a phenomenon known as pesting. In this work, we comprehensively investigate the role of Zr in mitigating pesting in MoSi2 using density functional theory calculations. We show that Zr dopants reduce the embrittling effects of oxygen interstitials at MoSi2 grain boundaries by being a charge donor to oxygen. However, a more substantial effect is observed when Zr is present as a secondary getter nanoparticle phase. Oxygen interstitials have a strong thermodynamic driving force to migrate into the Zr subsurface at the Zr/MoSi2 interface, and the work of separation of the clean and oxygen-contaminated Zr/MoSi2 interfaces are much higher than that of MoSi2 grain boundaries. Finally, we present an efficient screening approach to identify other potential getter elements using simple thermodynamic descriptors, which can be extended to other alloy systems of interest. These findings provide crucial fundamental insights and further avenues to optimize Mo and other alloys. (C) 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据