Twinning induced by asymmetric shear response

Abstract

Twinning, a plastic deformation mode, is crucial in dictating material plasticity and significantly impacting their mechanical properties. In this work, we propose a new twinning mechanism based on the phenomenon of asymmetric shear response. By integrating transition state theory with this mechanism, we derive the twinning nucleation stress, and reveal the impact of temperature and strain rate on twin nucleation and growth processes. The model's efficacy is validated through a comparison of predicted results for face centered cubic (FCC), body centered cubic (BCC) and hexagonal close packed (HCP) crystals with experimental ones. This work provides a theoretical foundation for predicting the conditions under which twinning occurs, thereby guiding the design and fabrication of materials containing twin structures.