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 $\left\{10\overline{1}1\right\}$ 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.