Micromechanical modeling of the martensitic transformation induced plasticity in steels

A micromechanical model is developed to predict the overall behavior of a representative volume element (RVE) of a material undergoing non-thermoelastic martensitic phase transformation. The theoretical approach is based on the evaluation of the energy dissipation using the concept of moving boundaries. Assuming an ellipsoidal growth of martensitic microdomains and taking into account some physical aspects typical of martensitic phase transformation in ductile materials, the obtained dissipation is reduced to a more simple form leading one to choose the volume fractions of each possible martensitic variants as the internal variables describing the microstructure evolution. The nucleation and growth conditions of a martensitic microdomain are derived using, simultaneously, the classical inelastic inclusion problem together with interface operators. The obtained results are combined with kinetics and kinematics studies to derive the constitutive equation of an austenitic single crystal from which the overall behavior of a polycrystalline RVE is deduced using the self-consistent scale transition method. Comparison with experimental data shows good agreement.