Modeling the role of external stresses on the austenite-to-bainite phase transformation in 51CrV4 steel

A new model is proposed to successfully predict the initiation and evolution of the austenite-to-bainite phase transformation, capturing specifically the time-dependent transformation kinetics. In particular, the isothermal bainitic transformation in 51CrV4 steel is experimentally observed for various constant stress conditions, and significant improvement is obtained in comparison with the existing models. Specifically, both the transformation kinetics and the resultant transformation strains can be simultaneously predicted using the same variant growth approach. Simulation results are in good agreement with the experiments, evidencing the success of the proposed model in describing the transformation phenomena in terms of kinetics and transformation plasticity. Furthermore, the proposed formulation provides a basis for incorporating variant–variant interactions and cementite formation in the residual austenite matrix.