THREE-DIMENSIONAL PHASE FIELD STUDY ON STRAIN SELF-ACCOMMODATION IN MARTENSTIC TRANSFORMATION

Abstract

The number of martensitic variants depends on the grain size and orientation of parent phase. Although the growth of polytwin structure with the combination of different martensitic variants was studied by in situ dynamic observation, the energy change during the growth of martensite cannot be revealed, and in turn the strain self-accommodation of martensitic transformation (MT) cannot be confirmed. Based on the recent study of the phase field model, describing proper martensitic transformation for a single-crystal system under a fully constrained boundary, a three-dimensional (3D) phase field simulation is performed to demonstrate the microstructure evolution of plolytwin structure in this paper, meanwhile, the energy change during the growth of martensite is calculated. The results indicate that during the growth of two martensitic variants the total strain energy increases with prolonging microstructural evolution time, however, the opposite change occurs during the growth of three martensite variants. The 3D phase field simulation reveals that the growth of three martensitic variants possesses the best strain self-accommodation effect.