The formation of H bubbles at small-angle tilt grain boundaries in W films.
The formation of H bubbles at small-angle tilt grain boundaries in W films.
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DOI：
10.1039/c6cp06178h
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发表时间：
2016-12
期刊：
影响因子：
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通讯作者：
Zhihai He;H. He;R. Ding;B. Pan;J. Chen
中科院分区：
文献类型：
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作者：
Zhihai He;H. He;R. Ding;B. Pan;J. Chen
The accumulation of H at the small-angle tilt grain boundary (GB) in the W(001) surface is investigated, on the basis of the first-principles calculations. By exploring the solution and diffusion behaviors of H at the GB, we find that the small-angle GB can capture the H atoms nearby, serving as a nucleation site of H bubbles. With the increasing number of trapped H atoms, the GB expands gradually, and the GBs can be unripped with an areal density of H up to 5.0 × 1015 H atoms per cm2, leading to the formation of H bubbles. Moreover, H2 molecules are observed, when the areal density of H atoms in GB is over 6.6 × 1015 atoms per cm2. According to our calculations, we propose a possible formation mechanism of H bubbles observed in the experiment, which is valuable for improving the service performance of W as a plasma-facing material in nuclear fusion reactors.
