Unstable twin in body-centered cubic tungsten nanocrystals

作者：Xiang Wang, Jiangwei Wang, Yang He, Chongmin Wang, Li Zhong, Scott X. Mao · 发表于：Nature Communications · 年份：2020 · 被引用次数：81 · 研究领域：Microstructure and mechanical properties、Boron and Carbon Nanomaterials Research、High-Velocity Impact and Material Behavior

Twinning is commonly activated in plastic deformation of low stacking-fault face-centered cubic (Fcc) metals but rarely found in body-centered cubic (Bcc) metals under room temperature and slow strain rates. Here, by conducting in situ transmission electron microscopy (TEM) at atomic scale, we discover that, in stark contrast to those in most Fcc metals, a majority of deformation twins in Bcc metals are unstable and undergo spontaneously detwinning upon unloading. Such unexpected instability of Bcc twins is found to be closely related to the prevalence of the inclined twin boundaries-a peculiar structure where twin boundaries are not parallel to the twinning plane, and the degree of instability is in direct proportion to the fraction of the inclined twin boundary. This work provides significant insights into the structure and stability of deformation twins in Bcc metals.