On the unified micromechanics constitutive description of one-way and two-way shape memory effects

A micromechanics constitutive model for the two-way shape memory effect (TWSME) of single crystal shape memory alloys is proposed to describe the TWSME behavior during the cooling and heating process after some training of the alloys. The model is established on two physical bases: (1) the micromechanics crystallographic constitutive theory of single crystal recently developed by SUN et al.[3] and (2) the analysis of the stored elastic strain energy due to dislocations that are produced in the training process of a single kind of variant and the analysis of the interactions between the stress fields of dislocations and transformations. Theoretical predictions of the model are in agreement with the available experimental observations. Finally the present model can be used as a theoretical basis to predict the TWSME of polycrystals.