Kinematics, Free Energy and Dissipation in the Case of Transformation Induced Plasticity (TRIP)

The aim of this work is to derive the behavior for an austenitic single crystal from which the overall behavior of polynystalline TRIP steels can be deduced using classical scale transition method. The micromechanical modeling is based on the kinematics, kinetics and continuum-thennodynamics of the martensitic transformation. Plastic strains of product and parent phases as we11 as the volume fractions of each martensitic variants are taken as the internal variables describing the miaostructure 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.