The Interaction between He Bubble and Migrating Grain Boundary Induced by Shear Loading

This work reveals the interaction mechanism between He bubble and grain boundary (GB) in bicrystal copper under shear loading via molecular dynamics simulations. The influences of He/vacancy ratio R_He/V, temperature T₀, and bubble diameter D₀ on the interaction mechanism are clarified. Specifically, two interaction modes, i.e., the GB traverses or is pinned on He bubble, are observed by changing the initial R_He/V, T₀, and D₀. As R_He/V increases, the influence of He bubble on GB migration shows a decrease–increase trend. Different He bubble evolutions are demonstrated by comparing their shapes, pressure, and volume. In the cases of low R_He/V, the medium temperatures (10–300 K) are found to accelerate the GB migration, but higher temperatures (600–900 K) will lead to the change in interaction mode and deteriorate the interaction process. Furthermore, a more noticeable bubble-drag effect on GB migration is observed in the samples with larger He bubble.