Effect of tensile rate on structural transformation and dislocation of magnesium single crystal based on molecular dynamics

Abstract

Magnesium and its alloys have broad application prospects as lightweight materials, but there are few studies of crystal and dislocation lines based on the molecular level of magnesium single crystal. In this study, the molecular dynamics method was used to establish the magnesium single crystal model, the properties of magnesium single crystal at different tensile rates at 300 K were studied. The results of stress - strain, Potential-strain, crystal structure change and dislocation density were analyzed. The results show that with the increase of tensile rate, the corresponding stress peak increases gradually, the corresponding strain value at the peak also increases, and the emergence of dislocation line generally lags behind the peak stress point. Come first and play a leading role was 1/3<-1100> incomplete dislocation and unknown dislocation, followed by 1/3<11-20> dislocation. At the peak point, the crystal structure begins to change from hexagonal-closest packing structure to other structures, after the peak, body-centered cubic and face-centered cubic structures begin to appear. With the increase of tensile rate, the corresponding strain increases gradually when body-centered cubic and face-centered cubic structures appear. The results are of great significance for the study of the deformation mechanism of magnesium single crystal