Investigation of twin-dislocation interactions using a novel discrete dislocation plasticity framework

Twinning-induced strain localization fundamentally governs a material’s ductility and failure mechanisms, complementing the role of dislocation slip in hexagonal close-packed crystals. This localization not only accommodates externally applied deformation through stress redistribution but also generates heterogeneous stress that significantly influences nearby dislocation evolution. In conventional dislocation-scale modeling approaches, such as discrete dislocation plasticity (DDP), twinning is typically represented by introducing twin boundaries and regions with reoriented crystal lattices. These models, however, often neglect the associated strain fields generated during the twinning process, resulting in an incomplete description of twinning-dislocation interactions. To address this limitation, a novel DDP model incorporating twin-induced heterogeneous deformation was developed. The model explicitly includes different stages of twinning, such as nucleation, propagation, and growth, and implements the twin-induced stress field using the classical Eshelby inclusion solution. A new superposition framework was further constructed to capture these stress contributions within the DDP formulation accurately. Based on this model, the experimentally observed characteristic twin-induced dislocation arrays in single crystals and bicrystal were successfully reproduced. Moreover, through comparison with the twin-free model, twin-dislocation interactions in polycrystals were quantitatively analyzed, demonstrating the capability of the model to resolve complex plasticity mechanisms across different microstructures.