The Microstructure Evolution of Lean Duplex Stainless Steel 2101

The microstructure evolutions of lean duplex stainless steel 2101 (LDX2101) and duplex stainless steel 2205 (DSS2205) during hot deformation at 1000–1200 °C and a strain rate of 10 s−1 are investigated. The experimental results show that the difference in the two-phase hardness of LDX2101 is greater than that in the case of DSS2205. In LDX2101, excess strain is therefore concentrated in the ferrite phase and strain transfer to the adjacent austenite phase is difficult. This also leads to greater stress concentration along the phase boundary in LDX2101, leading to edge cracking. The excess strain partitioning in ferrite leads to ferrite restoration occurring far in advance of austenite deformation, and the recrystallization of austenite is delayed accordingly. This further increases the microhardness difference between ferrite and austenite. The effects of Ni and Mn on the hot-deformation behavior are investigated.