The driving force for twin boundary migration in phase field model coupled to crystal plasticity finite element

Abstract

Deformation twinning, a critical deformation mechanism in metal with low-symmetry crystal structures, accommodates localized shear and reorientates a domain with a specific shear and rotation angle. Twin propagation and thickening occur via twinning dislocations/disconnections at the atomic scale, while at larger scales they are governed by the migration of twin boundaries. Phase field (PF) and other continuum methods for modeling deformation twinning often incorporates self-stress effects arising from boundary defects. These self-stress fields, which are singular or discontinuous, introduce artificial forces that distort interface behavior, leading to inaccuracies in predicting interface migration and microstructure evolution. To address this issue, we propose a stress correction scheme that diminishes self-stress effects on the migration of twin interfaces. By analyzing stress field characteristics associated with three-dimensional twins with sharp or diffuse interfaces using dislocation theory and crystal plastic finite element (CPFE) method, we introduce a “correction zone” to redefine the driving force. This approach interpolates stress outside the corrected region to provide an approximate representation of the interface driving force. Validation within the CPFE framework confirms that the scheme effectively diminishes self-stress influences. Finally, we implement the correction scheme in the CPFE-PF model to simulate the dynamic evolution of a three-dimensional twin and demonstrate the twin interface migration behavior compared to the scenario that using the stress containing self-stress as driving force.