First principles assessment of helium trapping in Y{sub 2}TiO{sub 5} in nano-featured ferritic alloys
- School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China)
- School of Materials Science and Engineering, Central South University, Changsha 410083 (China)
- Materials Department, University of California, Santa Barbara 93106 (United States)
- National Key Lab for Reactor Fuels and Materials, Nuclear Power Institute of China, Chengdu 610041 (China)
Nano-scale Y{sub 2}Ti{sub 2}O{sub 7} and Y{sub 2}TiO{sub 5} oxides are the major features that provide high strength and irradiation tolerance in nano-structured ferritic alloys. Here, we employ density functional theory to study helium trapping in Y{sub 2}TiO{sub 5}. The results suggest that helium is more deeply trapped in Y{sub 2}TiO{sub 5} compared to Y{sub 2}Ti{sub 2}O{sub 7}. Helium occupies open channels in Y{sub 2}TiO{sub 5}, where it weakly chemically interacts with neighboring oxygen anions, and results in less volume expansion compared to Y{sub 2}Ti{sub 2}O{sub 7}, reducing strains in the iron matrix. The corresponding helium mobility in these channels is very high. While its ultimate fate is to form oxide/matrix interface bubbles, transient deep trapping of helium in oxides plays a major role in the ability of NFA to manage helium distribution.
- OSTI ID:
- 22305780
- Journal Information:
- Journal of Applied Physics, Vol. 116, Issue 14; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
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