J. Phys. IV France 05 (1995) C8-227-C8-232
Micromechanical Approach of the Fatigue Behavior in a Superelastic Single CrystalE. Patoor, N. Siredey, A. Eberhardt and M. Berveiller
Laboratoire de Physique et Mécanique des Matériaux, URA 1215 du CNRS, Institut Supérieur de Génie Mécanique et Productique, Université de Metz, Ile du Saulcy, 57045 Metz cedex, France
Mechanical cycling of superelastic alloys leads to significant change in their observed behavior. Critical stress needed to induce the martensitic transformation is reduced while the tangent transformation modulus is increased. Microstructural observations have shown that a mechanical cycling produced a strongly oriented pattern of dislocations. This dislocation network is associated to an internal stress field. It seems reasonable to relate this internal stress field to the observed evolution of the mechanical response. This is phenomenologically performed in this work considering the thermodynamical potential associated to the martensitic transformation of a single crystal of parent phase in presence of a microstructure of defects. Evolutions of the microstructural state are defined using the volume fraction associated to the variant of martensite and additional volume fractions of defects related to the dislocation pattern. Results such obtained well-captured experimental observations.
© EDP Sciences 1995