ON THE THEORY OF CARBONITRIDE NUCLEATION KINETICS IN MICROALLOYED AUSTENITE

On the base of the critical analysis of existing models of strain induced precipitation of carbonitrides in austenite of microalloyed steels, a new kinetic model is developed. The driving chemical force for nucleation of carbonitrides can be calculated within the framework of Hillert and Staffansson’s regular solution theory, which treats carbonitrides as a binary mixture of carbides and nitrides, allowing further analysis of the nucleation kinetics using the formalism of Reiss’ binary nucleation theory. The nucleation rate calculated using this approach can differ significantly from the predictions of earlier models that used classical nucleation theory for singlecomponent (unary) systems.