Deformation mechanisms in aluminum single crystal : multi-scale dislocation dynamics analyses -

Abstract

Multiscale Dislocation Dynamics Plasticity (MDDP) simulations are carried out to investigate the mechanical response of Aluminum single crystals subjected to extreme conditions. The effects of temperature and strain rate on the dynamic yield point are studied in details. In doing so, an atomistically informed generalized dislocation mobility law is incorporated in MDDP. Additionally, pressure and temperature dependent elastic properties are employed to better capture the shockwave characteristics at elevated temperatures. The simulation results reveal unusual thermal hardening effect along with strain rate hardening behavior. Based on the simulations’ findings, a physically based constitutive equation for the dynamic yield strength is proposed. Moreover, we have conducted detailed analyses of the dislocation microstructural evolution and a dislocation density evolution model is presented.