Nanosize vacancy clusters, characterized in metals after plastic deformation, irradiation or specific heat treatments are suspected to participate in materials hardening through their interactions with mobile dislocations. Our numerical simulations made from combining three different simulation techniques, i.e., molecular statics, kinetic Monte Carlo and elastic line models allow us to compute the dislocations velocity in realistic conditions of applied shear stress, temperature, concentration, and size of the vacancy clusters, in face–centered-cubic aluminium. We show that the clusters behave as sources of vacancies that follow a reaction path along the dislocation line, which is recognized as a pipe diffusion process. The accumulation of vacancies in the dislocation stacking fault ribbon yields jogs that participate in the dislocation climb. Both vacancy leaks from clusters and climb of dislocation segments contribute to the dislocation crossing, which remains thermally activated. We integrated the ensemble of the thermally activated processes: Diffusion, emission, absorption processes, as well as dislocation-cluster crossing, into the same simulation allowing us to predict the dislocation mobility in good agreement with experimental deformation tests.

• Received 19 February 2020
• Revised 13 May 2020
• Accepted 18 September 2020

DOI:https://doi.org/10.1103/PhysRevMaterials.4.103603