Micromechanical modeling of martensitic transformation induced plasticity (TRIP) in austenitic single crystals

• Published in: International journal of plasticity 1998, Vol.14 (7), p.597-626
• Main Authors: Cherkaoui, M., Berveiller, M., Sabar, H.
• Format: Article
• Language: English
• ISSN: 0749-6419; 1879-2154
• DOI: 10.1016/S0749-6419(99)80000-X

Thermoelastic martensitic transformation can be controlled by external stress and/or temperature to produce the thermoelastic shape memory effect. The thermomechanical behavior of shape memory alloys has been modeled in the framework of continuum mechanics and micromechanics. Martensitic phase transformation in ductile materials, like iron-base alloys, has allowed the development of steels with high ductility and ultimate tensile strength. In ductile materials exhibiting nonthermoelastic martensitic transformation, the problem is more complicated because of the coupling between the different strain mechanisms (plastic flow of product and parent phases, transformation strain field) at the microscale. Except some phenomenological descriptions and finite element calculations, the study of the constitutive law for the TRIP steels is as yet much less developed as compared with shape memory alloys. The aim of this work is to derive the behavior for an austenitic single crystal from which the overall behavior of polycrystalline TRIP steels can be deduced using classical scale transition method. The micromechanical modeling is based on the kinematics, kinetics and continuum-thermodynamics of the martensitic transformation. Plastic strains of product and parent phases as well as the volume fractions of each martensitic variants are taken as the internal variables describing the microstructure evolution of the single crystal. From the derived Helmholtz free energy and dissipation, we obtain the driving forces acting on these internal variables according to the irreversible thermodynamic formalism. First results are presented and discussed in the case of a thermomechanical shear test.