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arXiv · 1101.2939

Threshold concentration for H blistering in defect free W

W. Xiao·G. -N. Luo·W. T. Geng
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Abstract

Lattice distortion induced by high concentration of H is believed to be precursor of H blistering in single crystalline W (SCW) during H isotope irradiation. However, the critical H concentration needed to trigger bond-breaking of metal atoms presents a challenge to measure. Using density functional theory, we have calculated the formation energy of a vacancy and a self-interstitial atom (SIA) in supersaturated defect-free SCW with various H concentrations. When the ratio of H:W exceeds 1:2, the formation of both vacancies and self-interstitials becomes exothermic, meaning that spontaneous formation of micro-voids which can accommodate molecular H2 will occur. Molecular H2 is not allowed to form, and it is not needed either at the very initial stage of H blistering in SCW. With supersaturated H, the free volume at the vacancy or SIA is greatly smeared out with severe lattice distortion and more H can be trapped than in the dilute H case.

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W. Xiao, G. -N. Luo, W. T. Geng. 2011-01-15. Threshold concentration for H blistering in defect free W. https://doi.org/10.1016/j.jnucmat.2011.09.019

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