A Multi-Phase Model for High Strength Steels

It is difficult to evaluate the strain hardening behavior of multi-phase steels while considering the stress-strain response of individual phases, due to the different deformation state and complex interactions of the soft and hard constituents during plastic forming. With assuming that the strain energy density of material equals to the weighted sum of each phase in this study, a multi-phase physical combined model is developed by incorporating the dislocation evolution of individual phases. The dislocation evolution of every individual phase is based on its micro-deformation, which is related to the macro-strain of material. The proposed model is verified by two groups of dual phase (DP) steels. One group considers different strength grades, and the other group deals with different martensite volume fractions (Vm). The strain hardening behaviors of material and individual phases are evaluated subsequently.