Thermodynamic‐ M echanical Modeling of Strain‐ I nduced α′‐ M artensite Formation in Austenitic Cr– M n– N i As‐ C ast Steel

The microstructure evolution during deformation and the mechanical behavior of an austenitic Cr–Mn–Ni as cast steel are investigated at various temperatures. The deformation‐induced twinning and ϵ/α′‐martensite formation – the TWIP and TRIP effects – occur in the investigate steel depending on the deformation temperature. For characterization and illustration of the TRIP/TWIP effects the STT and DTT diagrams are developed. Finally, the α′‐martensite nucleation threshold is determined, and an equation is proposed to describe the volume fraction of strain‐induced α′‐martensite as a function of the total driving force.