Stability of single-atomic-layer-height disconnections on (101¯2) twin boundary in Mg

Four different configurations of single-atomic-layer-height disconnections on ( 10 1 ¯ 2 ) twin boundary in magnesium are investigated using molecular dynamics simulations. It is found that a prismatic-basal (PB) single-atomic-layer-height disconnection is more stable than a basal-prismatic (BP) single-atomic-layer-height disconnection when each of them is connected with an I1 stacking fault associated with a stacking sequence change of BA B CB. In contrast, a BP single-atomic-layer-height disconnection is more stable than a PB single-atomic-layer-height disconnection when each of them is connected with an I1 fault associated with a stacking sequence change of AB A CA. A stable BP (or PB) single-atomic-layer-height disconnection can transform to a stable PB (or BP) single-atomic-layer-height disconnection when its step orientation changes with a change in the lying plane of the connected I1 fault.