Modeling the evolution of the dislocation density and yield stress of Al over a wide range of temperatures and strain rates

Abstract

This paper introduces an extended model for the evolution of internal and wall dislocation densities in pure aluminum during plastic deformation. The approach takes the three internal state variables (3IVM) model as a starting point and advances it by taking into account the dynamic annihilation of immobile/locked dislocations as well as dislocations stored in the subgrain/cell walls. The strength of the material, as one of the properties affected by dislocation density, is used to validate the model. Experimental flow curves for pure Al are taken as the basis for calibration. Compression tests are performed at temperatures from − 196 °C to 500 °C with strain rates of 1, 0.1, and 0.01 s−1. The effect of temperature and strain rate on each state parameter is illustrated and discussed.