Double twin-like crystalline reorientations in Mg single crystals: Molecular dynamics simulations

Abstract

Two types of double twin-like crystalline reorientations have been observed in the tension of Mg single crystals by molecular dynamics method. One can be approximately described as a typical {101¯1}-{101¯2} double twin, while the interface between the primary {101¯1} twin and the secondary {101¯2} twin shows a zigzag appearance consisting of co-existing {101¯2} twin boundary and basal/prismatic interface. The other is formed by a prior reoriented crystal with a rugged boundary, and a following {101¯1} twin, while the basal/prismatic interface dominates the boundary between the reoriented crystals. These double twin-like crystalline reorientations with misorientation angles of about 66° randomly occur under the tension along or near the [12¯10]-axis. The migration of basal/prismatic interface and twin boundary is sensitive to the relationship of the crystalline orientation and the loading direction, which causes the reoriented crystal annihilating or growing. Moreover, the migration of special rugged grain boundary between the reoriented crystal and the matrix is revealed to be fulfilled by the local atomic rearrangements, which contributes to the growth of double twin-like reoriented crystals.