Micromechanics-based modeling of two-way memory effect of a single crystalline shape-memory alloy

A micromechanics-based Helmholtz free energy is obtained. Then, in the framework of irreversible thermodynamics, a kinetic relationship, a martensitic nucleation criterion and the reorientation criterion of martensitic variants are obtained. These relationships are valid for a three-dimensional proportional or non-proportional mechanical loading or a combination of mechanical and thermal loading. The two-way memory effect is simulated and compared quantitatively with experimental results. This simulation is based on the assumption that mechanical dissipation of active variants decreases during cycling (training). Copyright (C) 1997 Acta Metallurgica Inc.