MICROMECHANICAL MODELING OF SUPERELASTICITY IN SHAPE-MEMORY ALLOYS

Micromechanical methods developed to describe the thermomechanical beh avior of solids are applied to phase transition related problem. Resul ts obtained are compared with those obtained using a macroscopic pheno menological approach. This micromechanical analysis is based on a kine matical description of the physical strain mechanisms and a definition of a local thermodynamical potential. Volume fractions of the differe nt variants of martensite are chosen as internal variables to describe the evolution of the microstructural state of the material. This anal ysis determines local constitutive equations for the behavior. Global relationships are obtained using a self consistent scheme. This approa ch gives results in good agreement with experimental observations perf ormed on Cu-based Shape Memory alloys.