Strength‐Ductility Synergy in an Austenitic Stainless Steel Processed by Warm Rolling and Subsequent Cryogenic Treatment

The austenitic stainless steel undergo warm rolling, followed by cryogenic treatment. The warm-rolled and cryogenically treated (WR-CT) sample exhibits superior strength and ductility compared to the warm-rolled (WR) sample, achieving a yield strength of 949 MPa and an elongation of approximate to 56.2%. The enhanced strength is attributed to the higher dislocation density, additional grain refinement, and the presence of martensite in the WR-CT sample. The WR and WR-CT samples exhibit similar deformation mechanisms. In the initial stage, dislocation slip predominantly governs the deformation. During the intermediate stage, the transformation-induced plasticity (TRIP) effect dominates the deformation mechanism. In the final stage, nearly all austenite transforms into martensite, and deformation mainly occurs via dislocation slip within the martensite phase. However, in the WR-CT sample, the TRIP effect is delayed during the stable processing stage (approximate to 8-23%) due to the higher mechanical stability of austenite, resulting from further grain refinement and higher dislocation density. Additionally, the coordinated deformation of strain-induced martensite with varying orientations contributes to delayed necking, achieving an optimal balance between strength and ductility.