Molecular dynamic simulation of edge dislocation-void interaction in pure Al and Al-Mg alloy

Abstract

In this study, the interaction of edge dislocations with nano-scale voids was investigated for the face centered cubic (FCC) structure of pure aluminum and Al-Mg alloy. The effect of Mg solute atoms on the Peierls stress (required for dislocation motion) at different temperatures, and the critical resolved shear stress (CRSS) for dislocation-void interaction was investigated in this study. In addition, the influences of void diameter (1, 2 and 3nm), inter-void distance (7.5 and 15nm) in a void array, and of temperature (300K) on resolved shear stress were determined. It was found that substitutional Mg atoms was highly effective on improving the mechanical behavior of the Al lattice and on the type of dislocation-void interaction (simultaneous or separate passing of partial dislocations). In addition, it was obtained that no void-induced climbing occurred during the interactions for these systems. Higher void diameter and in particular lower inter-void spacing led to a considerable increase in the CRSS, while the latter changed the type of dislocation-void interaction. Finally, it was shown that Peierls stress was decreased for pure aluminum from 0K to 10K, while different results were obtained for Al-Mg alloy that were discussed in detail.