Evaluating the influence of non-glide strain on prismatic dislocation in Mg using density functional theory calculations and the Peierls–Nabarro model

Abstract

Mg and Mg alloys frequently exhibit anisotropic mechanical properties. Various high strength Mg alloys have been developed recently. Since the effect of non-glide stress on slip deformation can be prominent under a large strain or stress, it is crucial to examine the effect of non-glide stress/strain on dislocation motion. Mg easily undergoes 〈a〉 dislocation at ambient temperature; hence, in this study, the generalized stacking fault (GSF) energy of 〈a〉 dislocation on prismatic {101¯0} planes under non-glide strains was examined using the density function theory. To comprehend how dislocation behaves under various conditions, the relation between GSF energy and Peierls stress based on the discrete Peierls–Nabarro model was established, and screw and edge dislocation behaviors in the prismatic plane were discussed to obtain deeper understanding. While the dislocation core width decreases with compression and increases with tension, the Peierls stress increases greatly with compression and reduces slightly with the application of tension.