On the strain-induced martensitic transformation process of the commercial AISI 304 stainless steel during cyclic loading

Low-cycle fatigue tests were performed on metastable austenitic steel at two initial material states, the as received, with a high crystal defect density, and the solution treated one, with fewer crystal defects. Cyclic curves have shown different hardening behavior depending on the initial material states. To understand these differences, the back and friction stresses were studied from the hysteresis loop analysis. The correlation of these results with the volume fraction of induced martensite and the observed microstructure revealed that the cyclic hardening behavior strongly depends on the existence of potential martensite nucleation sites.