| Abstract Scope |
Twinning is not only a basic deformation model but also can act as an effective way to improve the mechanical property of materials. However, Twinning is hardly activated in body-centered cubic (Bcc) metals under room temperature and slow strain rates. Here, by performing in situ high-resolution transmission electron microscopy (HRTEM), we found that a majority of deformation twins in Bcc metals are unstable and undergo spontaneously detwinning upon unloading, in stark contrast to those in most Fcc metals. Such unexpected instability of Bcc twins was associated with 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. |