A thermo-kinetic model for martensitic transformation kinetics in low-alloy steels

Abstract A thermo-kinetic model considering driving force-dependent activation energy, was developed, which can well describe the martensitic transformation upon continuous cooling in Fe-0.2C-1Mn-1Si (wt. %) model alloy and other low-alloy steels. Effects of prior austenite grain size (PAGS), as well as the autocatalytic nucleation, were illuminated. From the modeling, a phenomenological correlation between the driving force (thermodynamics) and the activation energy (kinetics) for martensitic transformation was established, suggesting that accompanying the increase of driving force, the activation energy for the transformation decreases.