Energetically favorable dislocation/nanobubble bypass mechanism in irradiation conditions

With exposure to high-energy particle irradiation, structural metals develop a number of nanoscale defects, one which is the nano-sized He bubble. Formed throughout material, these bubbles can directly impair movement dislocations and dramatically alter mechanical performance. Propagating edge in face-centered cubic metals, driven under sufficient forces, are expected cut through bubbles, due higher energetic expense. Here, using atomistic simulations for model Cu we find that when He-vacancy ratio bubble diameter become sufficiently large spacing reduced below threshold, an extended dislocation engages multi-step-bypass (MSB) maneuver change its glide plane overcome at room temperature. This unanticipated MSB mechanism provides more energetically favorable pathway compared conventional bypass mechanisms severe conditions.