Interaction of He with Cu, V, and Ta in bcc Fe: A first-principles study

Journal Article · Fri Jul 01 00:00:00 EDT 2011 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.3602156· OSTI ID:22036651

Yan, J X; Tian, Z X; Xiao, W; Geng, W T ^[1]

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1. School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China)

Precipitates often play key roles in improving the mechanical performance of structural materials. Using first-principles density functional theory method, we have calculated the geometry and energetics of small X{sub n} and X{sub n}He (X = Cu, V, and Ta) clusters in bcc Fe matrix to investigate the effect of He on X precipitation on the initial stage in neutron-irradiated Fe alloys. Both substitutional and interstitial He attract solute atoms. The attraction of a substitutional He and a Cu atom is as strong as 0.30 eV (nearest neighbor) or 0.25 eV (next-nearest neighbor), even stronger than the vacancy-Cu pair. Such an attraction facilitates the clustering of Cu atoms. By comparison, the attraction of He to V (0.02 eV) or Ta (0.22 eV) is weaker than that of a vacancy. We find that one He can bind up to four Ta atoms to form a tetrahedron, despite the fact that in the absence of He, Ta atoms prefer to stay away from each other. The effect of He on the solute-solute and solute-matrix interactions can be understood from the facts that He behaves both as a free-volume filler and as a bonding insulator.

• OSTI ID: 22036651
• Journal Information: Journal of Applied Physics, Vol. 110, Issue 1; Other Information: (c) 2011 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
BCC LATTICES
COMPARATIVE EVALUATIONS
COPPER ALLOYS
CRYSTALS
DENSITY FUNCTIONAL METHOD
ELECTRONIC STRUCTURE
HELIUM
INTERSTITIALS
IRON ALLOYS
IRRADIATION
MATRIX MATERIALS
NEUTRON FLUENCE
PHYSICAL RADIATION EFFECTS
PRECIPITATION
SOLUTES
TANTALUM ALLOYS
VACANCIES
VANADIUM ALLOYS