The stable configuration for a single-atomic-layer-height disconnection on the {101¯1} twin boundary

Abstract

Single-atomic-layer-height disconnections that connect with I1 stacking faults are produced on {101¯1} twin boundaries in pure magnesium through transmutation of basal 〈a〉 mixed dislocations across the twin boundaries, and their stabilities are examined using molecular dynamics simulations. The stable configuration for a single-atomic-layer-height disconnection is a pyramidal-basal (PyB) disconnection connecting an I1 fault associated with a stacking sequence change of ABACA, or a basal-pyramidal (BPy) disconnection connecting an I1 fault associated with a stacking sequence change of BABCB. A stable single-atomic-layer-height disconnection can transform to a less stable single-atomic-layer-height disconnection when its step orientation changes solely. A stable single-atomic-layer-height disconnection can also transform to another stable single-atomic-layer-height disconnection, when the step orientation of the disconnection and the type of the I1 fault that connects with the disconnection change synchronously, and this process is accompanied with the emission of a Shockley partial dislocation from the twin boundary.

Keywords

• Magnesium
• {101¯1} Twin boundary
• Molecular dynamics
• Single-atomic-layer-height disconnections
• I1 stacking fault