New insight into the helium-induced damage in MAX phase Ti₃AlC₂ by first-principles studies

Authors

Yiguo Xu, Division of Functional Materials and Nanodevices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang
Xiaojing Bai, Division of Functional Materials and Nanodevices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang
Xianhu Zha, Division of Functional Materials and Nanodevices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang
Qing Huang, Division of Functional Materials and Nanodevices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, ZhejiangFollow
Jian He, Laboratory of Biotechnology, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning
Kan Luo, Division of Functional Materials and Nanodevices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang
Yuhong Zhou, Division of Functional Materials and Nanodevices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang
Timothy C. Germann, Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico
Joseph S. Francisco, University of Nebraska-LincolnFollow
Shiyu Du, Division of Functional Materials and Nanodevices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, ZhejiangFollow

Document Type

Article

Date of this Version

2015

Citation

THE JOURNAL OF CHEMICAL PHYSICS 143, 114707 (2015)

Comments

Copyright 2015 AIP Publishing LLC.

Abstract

In the present work, the behavior of He in the MAX phase Ti3AlC2 material is investigated using first-principle methods. It is found that, according to the predicted formation energies, a single He atom favors residing near the Al plane in Ti3AlC2. The results also show that Al vacancies are better able to trap He atoms than either Ti or C vacancies. The formation energies for the secondary vacancy defects near an Al vacancy or a C vacancy are strongly influenced by He impurity content. According to the present results, the existence of trapped He atoms in primary Al vacancy can promote secondary vacancy formation and the He bubble trapped by Al vacancies has a higher tendency to grow in the Al plane of Ti3AlC2. The diffusion of He in Ti3AlC2 is also investigated. The energy barriers are approximately 2.980 eV and 0.294 eV along the c-axis and in the ab plane, respectively, which means that He atoms exhibit faster migration parallel to the Al plane. Hence, the formation of platelet-like bubbles nucleated from the Al vacancies is favored both energetically and kinetically. Our calculations also show that the conventional spherical bubbles may be originated from He atoms trapped by C vacancies. Taken together, these results are able to explain the observed formation of bubbles in various shapes in recent experiments. This study is expected to provide new insight into the behaviors of MAX phases under irradiation from electronic structure level in order to improve the design of MAX phase based materials.