Strategy to improve strength-ductility together in a 2101 lean duplex stainless steel

Abstract

In general, 2101 Lean Duplex stainless steel (LDSS) with the standard phase fraction in the range of 45–55 vol% austenite and ferrite exhibit strength around ∼500 MPa with ∼30 % ductility in the cold rolled and annealed condition. To obtain a higher strength-ductility combination while maintaining the standard phase fraction, the hot rolled and annealed samples of 2101 LDSS has been cold rolled in the range of 30–70 % reduction and short-time annealing at 910 °C or 1140 °C. The microstructures of the studied samples were evaluated by using optical microscopy, SEM, and EBSD analysis, and tensile properties were determined at room temperature. It was observed that simultaneous improvement in the strength and ductility at room temperature by applying the 30–50 % cold reduction and annealing at 910 °C for a short time (10 min). The partially recrystallized austenite-ferrite, along with the fresh strain-induced austenite, provides better yield strength compared to the fully recrystallized microstructure as the retained strain inside the phases increases the dislocation strengthening. The retained strain in the partially recrystallized austenite along with only a few fresh austenites, promotes instability by reducing the critical strain for deformation-induced martensite during tensile deformation and causes TRIP-induced ductility. The process has the potential to improve strength-ductility together in the lean duplex stainless steel. © 2025 Elsevier B.V.