The [formula omitted] non-cozone twin-twin interactions in Mg: A stability and mobility study using 3-D atomistic simulations

Abstract

Due to easy activation of tensile twinning in Mg, multiple {101¯2} twin variants can interact with each other and form twin-twin boundaries over the course of plastic deformation. Previous studies using 2-D settings provide only a partial understanding of these interactions, especially the non-cozone ones. Here, atomistic simulations are used to study the 3-D structural characteristic and evolution of the non-cozone {101¯2} twin-twin junctions. The study reveals the existence of new twin-twin boundaries (TTBs) such as TTBBP and TTBK2, formed after the interaction between the basal prismatic and conjugate twin interfaces with the coherent twin boundary. For both non-cozone twin-twin interactions, the {1¯21¯2} TTB and its associated twin-twin junctions are found to play a major role in the {101¯2} twin's stability and mobility. Specifically, they promote the growth of the 3-D twin in both the normal and forward directions during the interaction and hinder the detwinning process upon unloading.