FEM Simulation of the Martensitic Tranformation in NiTi Alloys

Abstract

Numerous studies have demonstrated the influence of elastic and plastic strain energies on the martensitic transformation in shape memory alloys. In recent years the Finite Element Method (FEM) has been applied to a wide range of elastic and plastic problems, however, few FEM analyses of shape memory phenomena have been reported. In this paper the FEM method has been used to model the martensitic transformation. The model assumes a two variant shear transformation in a two dimensional grain. Plastic deformation accompanying the transformation is accounted for using the Estrin-Mecking constitutive model. The spatial distribution of elastic and plastic strain energies developed during the transformation is shown to determine variant structure. Calculations of the effect of applied stress on variant structure and the effect of stress and repeated thermal cycling on the transformation temperatures are presented.