Interaction of H with stacking fault in W(111) film: A possible formation mechanism of H bubbles

The behavior of H atoms near a stacking fault in W(111) surface is extensively studied based on first-principles density functional theory calculations. We find that H near the stacking fault can be captured and trapped in this defect. These trapped H atoms significantly weaken and even break the W–W bonds in the stacking fault, inducing accumulation of more hydrogen atoms in the stacking fault. Our calculations predict the accommodating capacity of the stacking fault for H to be larger than 3.4 × 1015 cm−2, consistent with the experimentally observed H blistering in W-based fusion reactor materials.