Elastoplastic phase-field simulation of self- and plastic accommodations in Cubic→tetragonalCubic→tetragonal martensitic transformation

An elastoplastic phase-field (PF) model of martensitic transformation is proposed to study the effects of self- and plastic accommodations on the evolution of a stress-accommodating martensitic structure and elastic strain energy minimization. Cubic→tetragonalCubic→tetragonal martensitic transformation in elastic and elastoplastic materials is simulated using our elastoplastic PF model. The PF model can predict the self- and plastic accommodation behaviors during the martensitic transformation, which relax the transformation-induced stress field. Therefore, it can be shown that the elastic strain energy associated with the transformation is largely reduced by both accommodations. Our PF simulation also indicates that plastic deformation in the matrix arrests the growth of the tetragonal martensite phase, as suggested by some theoretical and experimental studies. In the evolution of the martensitic microstructure with both self- and plastic accommodations, we can find that the delay of the formation of the self-accommodating variant takes place, because the transformation-induced stress field is considerably relaxed by plastic deformation before self-accommodation. Furthermore, we can confirm that plastic accommodation largely reduces the elastic strain energy during the formation of the tetragonal phase that is affected by both self- and plastic accommodations, such as lath martensite formation, by the proposed PF model.