Martensitic transformation of an austenitic stainless steel under non-proportional cyclic loading

In this study, a series of cyclic tests on a 304L stainless steel with different loading paths were conducted. It revealed that as the non-proportionality of loading path increased, the growth rate of martensitic content became higher and its distribution among the austenitic matrix appeared more uniform. A phase transformation kinetics equation was modified to describe the effect of cumulative plastic strain, loading amplitude and loading path on martensitic transformation. A stress decomposition rule was proposed to incorporate both the non-proportional hardening and martensitic transformation hardening to describe the hardening mechanism.