Power-Law Creep from Discrete Dislocation Dynamics

TL;DR

This paper uses 2D discrete dislocation dynamics simulations to model power-law creep in aluminum, incorporating vacancy diffusion and dislocation climb, and successfully predicts creep rates consistent with experiments.

Contribution

It introduces a comprehensive simulation approach that couples dislocation glide, climb, and vacancy diffusion to explain power-law creep in metals.

Findings

Predicted creep rates match experimental data.

Dislocation climb and vacancy diffusion are key to power-law creep.

Quasi-equilibrium states enable long-term creep observations.

Abstract

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.