Martensite → austenite phase transformation kinetics in an ultrafine-grained metastable austenitic stainless steel

A generalized phase transformation kinetics model is used to understand the martensite to austenite transformation in a cold-rolled and annealed metastable AISI 301LN ultrafine-grained austenitic stainless steel. The model shows that the presence of interstitial nitrogen and heavy cold-rolling is important to promote fast transformation kinetics, through rapid nitrogen-diffusion and austenite nucleation at austenite/martensite phase boundaries.