Power-Law Creep from Discrete Dislocation Dynamics

We report two-dimensional discrete dislocation dynamics simulations of combined dislocation glide and climb leading to `power-law' creep in a model aluminum crystal. The approach fully accounts for matter transport due to vacancy diffusion and its coupling with dislocation motion. The existence of quasi-equilibrium or jammed states under the applied creep stresses enables observations of diffusion and climb over time scales relevant to power-law creep. The predictions for the creep rates and stress exponents fall within experimental ranges, indicating that the underlying physics is well captured.