Defect nucleation from a pre-existing intrinsic I1 stacking fault in magnesium by molecular dynamics simulations

Abstract

In order to clarify defect nucleation in the vicinity of a pre-existing intrinsic I1 stacking fault (SF) in magnesium (Mg), we carried out molecular dynamics (MD) simulations containing an I1 SF under several applied shear stresses, using a modified embedded atom method (MEAM) potential. Depending on stress states, different types of defects were generated from the I1 SF. Under shear stress on 0001 basal plane along 112¯0 direction, 112¯1 twin was formed from the side ends of the I1 SF. On the other hand, in the case of higher resolved shear stress (RSS) for c+a pyramidal slips, c+a partial dislocations were generated with SFs on the first-pyramidal planes as well as the second-pyramidal planes. The dissociation reactions of the dislocations at the side ends of the I1 SF were energetically evaluated, and it was implied that nucleation of the c+a dislocations on the first-pyramidal planes is more favorable than on the second-pyramidal planes. These results suggest that I1 SFs are attractive defects for nucleation of c+a dislocations.