Dual-interface model for twinning in the coupled crystal plasticity finite element – Phase field method

Abstract

Crystallographic shear transformation banding such as deformation twinning and martensitic transformation accommodates plastic deformation and generates new domain with different orientation or phase in matrix. The evolution of a new domain is described by the migration of interfaces separating the domain from the matrix. A coupled crystal plasticity finite element (CPFE) – phase field (PF) method is thus developed to simulate the migration of interfaces and plastic deformation. We propose a dual-interface model that integrates the constrained-sharp interface in FE method to solve the deformation fields, and the refined-diffuse interface in PF method to solve the domain evolution. The constrained-sharp interface in FE consists of one transition element between matrix and new domain. The refined-diffuse interface is locally extracted from the constrained-sharp interface by multi-classifier neural network fitting. Such a smoothing technique rubs off the jaggies of the constrained-sharp interface by a smooth function and thus diminishes mesh sensitivity of interface. Finally, we implemented the dual-interface model into the coupled CPFE-PF method and demonstrated the capability of diminishing mesh sensitivity in modelling deformation twinning.