Enhanced Mechanical Properties of Martensitic Stainless Steels Synergistically Regulated by the Composite Precipitation and Film‐Like Reverted Austenite

This study examines the mechanical properties and microstructural evolution of Fe–Cr–Ni–Ti–Mo martensitic stainless steel, focusing on the synergistic effect of aging temperature on precipitation and reverted austenite. The nonlinear variation in mechanical properties correlates with the evolution of nanoscale precipitates and changes in the fraction and morphology of reverted austenite. As aging temperature increases, reverted austenite forms along lath martensite boundaries, transitioning from film‐like to block‐like morphology. Aging at 500°C yielded optimal mechanical properties: ultimate tensile strength = 1765 MPa, yield strength (YS) = 1691 MPa, EL = 7.7%, RA = 16.9%, and Charpy impact energy = 18.5 J. This performance is attributed to a high density of nanoscale Ni 3 (Ti, Al) intermetallic compounds, Mo‐rich precipitates, and film‐like reverted austenite within the lath martensitic matrix. The strengthening mechanism is elucidated through theoretical models relating YS to microstructural characteristics. Furthermore, the enhancement of ductility and toughness is explained based on microstructural evolution under different heat treatment conditions, providing comprehensive understanding of structure–property relationships in martensitic stainless steels.