Difference between thermal-induced martensite and deformation-induced martensite in 304 austenitic stainless steel

This study investigates the differences between deformation-induced martensite (DIM) and thermal-induced martensite (TIM) in 304 austenitic stainless steel, focusing on their formation, distribution, and behavior during annealing. DIM was generated through cold rolling (CR), while TIM was produced via cryogenic treatment (CT). Microstructural characterization revealed that both martensite’s are distributed in blocky forms, with DIM exhibiting a finer grain structure compared to TIM. During the annealing process, both types of martensite undergo reverse transformations back to austenite, but DIM begins to reverse earlier at a slower rate. Consequently, after annealing, DIM yields a higher amount of reversed austenite (RA) with smaller grain size, whereas TIM transforms into fewer but larger RA grains. This study provides critical insights into the distinct phase transformation mechanisms of DIM and TIM, offering a deeper understanding of their effects on the microstructure and mechanical properties of 304 austenitic stainless steel. This knowledge is valuable for optimizing processing techniques and enhancing material performance in industrial applications.