Effect of critical tempering on microstructure evolution, mechanical performance, and corrosion behavior of a cast multiphase stainless steel

• Critical tempering at 610 °C yields the best strength-ductility balance (PSE=23.6 GPa·%) in a novel cast multiphase stainless steel. • Reverted austenite stability, governed by Ms and γSFE, drives TRIP and TWIP effects, enhancing mechanical performance. • Higher tempering temperatures cause Cr segregation and Cr-depleted zones, degrading corrosion resistance. • Multiphase coordinated deformation improves strength-ductility, but corrosion initiates at chemically inhomogeneous phase boundaries.