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Title: First principles assessment of helium trapping in Y{sub 2}TiO{sub 5} in nano-featured ferritic alloys

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.
Authors:
 [1] ; ; ;  [2] ;  [3] ; ;  [4] ; ;  [5]
  1. School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China)
  2. School of Materials Science and Engineering, Central South University, Changsha 410083 (China)
  3. (China)
  4. Materials Department, University of California, Santa Barbara 93106 (United States)
  5. National Key Lab for Reactor Fuels and Materials, Nuclear Power Institute of China, Chengdu 610041 (China)
Publication Date:
OSTI Identifier:
22305780
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 116; Journal Issue: 14; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; DENSITY FUNCTIONAL METHOD; DISTRIBUTION; EXPANSION; FERRITIC STEELS; HELIUM; INTERFACES; IRRADIATION; MOBILITY; NANOMATERIALS; NANOSTRUCTURES; OXIDES; OXYGEN; STRAINS; TITANATES; TRANSIENTS; TRAPPING; YTTRIUM COMPOUNDS