The original nucleation and migration of the basal/prismatic interfaces in Mg single crystals

TL;DR

This study uses molecular dynamics simulations to explore the nucleation, migration, and transformation of basal/prismatic interfaces in magnesium single crystals, revealing mechanisms that accommodate strain during deformation.

Contribution

It provides detailed atomic-level insights into BP interface behaviors, including nucleation, migration, and transformation, which were previously not well understood.

Findings

BP interfaces nucleate via shuffling mechanism.

Migration is influenced by disconnection types and misfit dislocations.

BP interfaces can transform into {10-12} twin boundaries.

Abstract

The formation of basal/prismatic (BP) interfaces accompanying with the nucleation and growth of a reoriented crystal in Mg single-crystals under c-axis tension is investigated by molecular dynamics simulations. The BP interfaces nucleate by shuffling mechanism via local rearrangements of atoms. Both two-layer disconnections and one-layer disconnections contribute to the migration of BP interfaces. In a three-dimensional view, the BP interfaces relatively tend to migrate towards the [1-210] direction rather than the [-1010]/[0001] direction since the misfit disconnection or misfit dislocation caused by the accumulation of mismatch along the [-1010] /[0001] direction impedes the disconnection movement. The BP interfaces can transform to the {10-12} twin boundary (TB) and vice versa. While the process from BP interface to TB is described as the linear pile-up of interface disconnections, the versa transformation is proposed as the upright pile-up process. Both BP transformation and {10-12} twinning can efficiently accommodate the strain along the c-axis, and the conjugate BP interfaces and {10-12} TBs account for the large deviations of twin interfaces from the {10-12} twin plane.