Effects of annealing on the micro-internal stress induced by interstitial defects in aluminum crystal by molecular dynamics simulations

Abstract

Micro-internal stress caused by self-interstitial defects in aluminum crystals was studied by using the molecular dynamics method. The effects of annealing on the lattice structure near the interstitial defects and the evolution of atoms near defects are analyzed. For octahedral, tetrahedral, and crowdion self-interstitial atoms, the atomic stress in the affected area after annealing decreases significantly compared with that before annealing. For dumbbell self-interstitial atoms, there are no obvious changes in atomic stresses in all regions before and after annealing. For four configurations of interstitial defects, the internal stress obviously decreased after annealing. Different concentrations of interstitial atoms have different effects on the internal stress and the size of the space region with internal stress. The size of the space region increases with the increase in concentration, and it can be reduced by annealing. When the concentration of interstitial atoms is within a certain range, annealing can effectively reduce the internal stress. When the concentration is low or high, annealing can only eliminate the internal stress in the local spatial regions and may increase the internal stress in other spatial regions.