A micromechanical modeling of the Greenwood–Johnson mechanism in transformation induced plasticity

An experimental analysis of transformation induced plasticity (TRIP) considering bainitic transformation in a 16MND5 steel (SA508Cl3 in ASTM norm) has been reported recently in the International Journal of Plasticity. Its main results have shown that among the existing models used in practical applications, the one proposed by Leblond 10 years ago seems to be one of the models which describes the more accurately the phenomenon. It was also noticed that this model leads to a singularity in the description of the TRIP at the beginning of the transformation under low applied stress. This singularity is usually avoided by the introduction of an arbitrary threshold. The TRIP norm at the end of the transformation seems also slightly overestimated by this model. The work which is presented here is devoted to an investigation of these discrepancies from a reevaluation of the micromechanical model as originally used by Leblond et al. A more complete formulation taking into account the elasticity in both phases will be developed and solved resulting in an improved model enabling a better description of the experimental results and removing the singularity mentioned above. A comparison between experimental results and the predictions of the proposed model is given.