Effect of Tensile Deformation on Microstructure and Material Properties of Hyper-Duplex Stainless Steel

The variations in the austenite-ferrite dual-phase structure of hyper-duplex stainless steels subjected to tensile deformation were analysed in the present work. The blocks of ASTM A890 7A hyper-duplex steel were cast and heat treated to obtain a clean dual-phase structure. Unilateral tensile stress was applied on specimens prepared from the blocks. Heat-treated specimens were deformed under a displacement control mode for various percentage elongations. Scanning electron microscope and metallurgical microscope images revealed that the austenite phase was more deformed compared to that of the ferrite phase. X-ray diffraction analysis was carried out to find the crystallographic planes where maximum deformation has occurred and to explain how different phases participated in the deformation process. The austenite phase was found to be far more deformed than the ferrite phase, with the greatest deformations in the (111) and (200) planes. The distribution of constituent alloying elements was evaluated using energy-dispersive X-ray analysis (EDAX) and area-scan techniques and it was found that there were no substantial changes in the concentration of alloying elements as a result of deformation.