Microscopic modelling of simultaneous two-phase precipitation: application to carbide precipitation in low-carbon steels

A thermodynamically-based precipitation model, employing the classical nucleation and growth theories, has been adapted to deal with simultaneous precipitation of metastable and stable phases. This model gives an estimation of the precipitation kinetics (time evolution of radius and density of precipitates for both phases, as well as the evolution of solute fraction) in a wide range of temperature. Results were successfully compared with an experimental isothermal precipitation diagram (Time–Temperature-Transformation, TTT) from the literature for the precipitation of ϵ carbide and Fe3C in low-carbon steels.