Microstructural Evolution and Hot Deformation Behavior of Lean Duplex Stainless Steel 2101

In this study, hot deformation behavior of lean duplex stainless steel 2101 (LDX2101) is investigated via isothermal compressive tests in the temperature ranges of 900-1 150 degrees C and the strain rate ranges of 0.01-10 s(-1). The effect of temperature and strain rate on the hot workability, strain partitioning and flow behaviour of LDX2101 is systematically investigated. It is found that the peak stress decreased with an increase in deformation temperature and a decrease in strain rate. The softening mechanism of the ferrite and austenite is dynamic recovery (DRV) and dynamic recrystallization (DRX), respectively. Further increasing the strain rate promote the DRX. The hot processing map was constructed in the sample. There are two flow instability regions at lower strain rate and lower temperature due to the lack of sufficient extra stress for the discrepancy of deformation coordination between the ferrite/austenite phases. Moreover, brittle Cr2N precipitates are observed along the ferrite/austenite phase boundaries, which can act microcracks initiation position. Considering the hot processing map and microstructural evolution in LDX2101, the optimum hot processing parameters for LDX2101 are found to be in a strain rate range of 0.01-10 s(-1) with the temperature range of above 1 050 degrees C and strain rate of 0.8-10 s(-1).

Automated summary

The hot deformation behavior of lean duplex stainless steel 2101 was investigated through isothermal compressive tests. The study found that peak stress decreased with increased deformation temperature and decreased strain rate, with softening mechanisms identified as dynamic recovery for ferrite and dynamic recrystallization for austenite. Flow instability regions may occur at lower strain rates and temperatures due to discrepancies in deformation coordination between ferrite and austenite phases.