Dislocation-modified high index twinning mechanisms in deformed magnesium alloy

A combination of high resolution transmission electron microscopy (HRTEM) and electron backscatter diffraction (EBSD) was applied to study the formation mechanism associated with high index twins in a deformed magnesium alloy. Utilizing the information obtained about the formation of high index twins by identifying their structural characteristics and interfacial atomic arrangement, we found that high index twins were obtained from dislocation-modified double twins. With increasing deformation, misorientations between the matrix and deformation twin increased, resulting in the evolution of double twins into a variety of structures. This discovery about high index twin formation can greatly improve the ability to identify various types of double twins in EBSD data. This mechanism provides a new insight into the formation of high index twins and aids in understanding the material fractures caused by double twinning. (C) 2019 Elsevier B.V. All rights reserved.