Microstructural and Mechanical Behavior of a Duplex Stainless Steel under Hot Working Conditions

In the hot deformation of duplex stainless steels, the complexity of microstructure evolution and mechanical response is increased compared to single-phase ferritic or austenitic stainless steels. This study aims to analyze the microstructural evolution and mechanical behavior of a duplex stainless steel in as-cast and wrought conditions under various deformation modes. Plane strain compression and torsion deformation modes were employed to investigate factors such as spatial phase distribution, interface nature, and relative mechanical properties of both phases. Utilizing the law of mixtures, the study explains the different flow curves observed when altering phase distribution and deformation modes. The results demonstrated that during the deformation of as-cast microstructures, the deformation partitions were heterogeneous between the phases, with some austenite regions acting as hard, nondeforming particles. The research indicated that cracks could initiate at the interfaces of these regions even at relatively low strains, while the initial Kurdjumov–Sachs orientation relationship between ferrite and austenite remained intact. These findings contribute valuable insights into the effective processing and application of duplex stainless steels.