Spectral phase-field model of deformation twinning and plastic deformation

Deformation twinning is critical to understanding and predicting the heterogenous deformation of many important material systems, e.g., hexagonal metals. In this work, we report a Fast-Fourier-Transform (FFT) based spectral phase-field method (PFM) model of deformation twinning and plasticity by directly incorporating the spectral FFT elasto-viscoplastic formulation, which allows two-way coupling between morphological evolution of deformation twinning and elastoplastic deformation. We verify the model by studying the twinning morphology evolution and plastic deformation of Mg single crystals and comparing the results with existing experimental measurements. We then apply the model to investigate heterogeneous twinning nucleation, growth and propagation behaviors, including twin-twin interactions, double twinning, and twin-grain boundary interactions. This work not only provides useful insights into the underlying deformation twinning mechanisms in hexagonal crystals but also presents an efficient PFM model of deformation twinning and plasticity which is generally applicable to modelling and predicting morphological evolution of deformation twinning and its effects on elasto-plastic responses of polycrystalline materials.