Temperature-sensitive phase-field modeling of strain-induced martensitic transformation in austenitic stainless steel

Austenitic stainless steels (ASSs) achieve superior strength-toughness synergy through strain-induced martensitic transformation (SIMT). Nevertheless, the temperature-dependent multiscale coupling mechanism of SIMT remains poorly understood, limiting accurate performance prediction under complex thermomechanical conditions. A strain-incremental isothermal tensile protocol is designed to capture the temperature-strain characteristics of 304 ASS from 20 to 95 °C, providing experimental data on stress-strain responses, martensite content, and microstructural features. An elastoplastic phase-field model is then developed based on the time-dependent Ginzburg-Landau (TDGL) equation, incorporating temperature-dependent free energy terms to quantify the effect of temperature on SIMT. A preset distribution of the martensite start temperature (M_s), derived from initial EBSD characterization, represents microstructural heterogeneity and enables the model to capture the temperature-dependent evolution of martensite under different straining conditions. Quantitative comparisons with experiments show that the model accurately reproduces the temperature-dependent evolution of both martensite content and stress-strain behavior. These results clarify the microscopic mechanism of temperature-regulated SIMT and establish a correlation framework linking temperature, strain, microstructure, and mechanical properties.