Synergistic Effect of Cold Rolling and Subsequent Annealing on the Austenite Stability and Mechanical Behavior of Duplex Stainless Steel

In this study, the evolution of mechanical properties and underlying deformation mechanisms of an economical duplex stainless steel (DSS) with different phase ratios is investigated while maintaining comparable grain sizes of ferrite and austenite under controlled heat treatment conditions. It is found that the mechanical characteristics of three DSS samples with different two‐phase ratios are significantly distinct, with almost equivalent yield strength, but significant differences in tensile strength and elongation, especially in the work hardening ability. Microstructural analysis shows that increasing the annealing temperature reduces the volume fraction while raising the stacking fault energy of austenite, which is a result of elements distributing themselves between ferrite and austenite. This change promotes a shift in the dominant deformation mechanism from transformation‐induced plasticity to twinning‐induced plasticity, resulting in a distinct strain hardening behavior. This study offers new insights into an economically viable high‐strength DSS for various application scenarios by adopting optimal heat treatment processes to achieve the desired microstructure configurations.