In situ atomistic observation of grain boundary migration subjected to defect interaction

Grain boundary (GB) migration associated with grain growth and recrystallization encounters lattice defects frequently, while the atomistic mechanisms of GB-defect interactions during these dynamic processes remain largely unclear. Here, we systematically investigate the atomistic mechanism of the interactions between migrating Σ11(113) symmetrical tilt GBs and different lattice defects, including full dislocation, stacking fault and nanotwin in Au, via the integrated in situ nanomechanical testing and molecular dynamics simulations. Experimental evidence demonstrated a conservative defect accommodation mechanism of Σ11(113) GB and a coupled GB-twin evolution, where localized atom displacement dominated the GB-defect interactions. Moreover, the shear-coupled GB migration was unperturbed by the interaction, due to the glissile residual disconnections left on the GB. These findings provide a comprehensive experimental understanding on the atomistic mechanism of GB migration under the influence of different lattice defects, which significantly advances the theoretical development of GB-dominated plasticity under more realistic circumstances.