MICROMECHANICS MODELING FOR THE CONSTITUTIVE BEHAVIOR OF POLYCRYSTALLINE SHAPE MEMORY ALLOYS .1. DERIVATION OF GENERAL RELATIONS

A MICROMECHANICS constitutive model has been proposed in this paper to describe the pseudoelastic and shape memory behavior of polycrystalline shape memory alloys under various temperatures. The derivation of the model is based on the thermodynamics, micromechanics and microstructural physical mechanism analysis of the material during deformation and it is shown that the inelastic deformation of the material in the mechanical and/or thermal loading processes is associated with some temperature, stress state and loading history dependent yielding surfaces which microscopically correspond to the forward and reverse transformation (or reorientation) processes, respectively.