Investigation on Hot Deformation Behavior and Microstructure Evolution of Lean Duplex Stainless Steel 2101 during Elevated Temperature Compression Testing

The hot deformation behavior and microstructure evolution of lean duplex stainless steel 2101 (LDX 2101) have been investigated using hot compression test in the ranges of 900-1200 degrees C and 0.01-10 s(-1). After kinetic analysis, the activation energy of LDX 2101 is determined to be 421.840 kJ mol(-1). The optimal parameter range for hot processing is 920-980 degrees C and 0.1-1 s(-1). The dynamic recrystallization mechanism is closely related to the subgrains and subgrain boundaries (SBs) pre-generated by dynamic recovery. Therein, the DRX mechanism of ferritic phase is continuous dynamic recrystallization (CDRX), which is characterized by disassembly and rearrangement of tangled dislocations located at SBs and subgrains progressive rotation (SGPR) to complete the transformation to recrystallized grains. The main DRX mechanism of austenite is discontinuous dynamic recrystallization with strain-induced boundary migration as the nucleation mode, which is characterized by subgrains on the pre-existing high-angle grain boundaries bowing into the ferrite to transform into austenite recrystallization grains by swallowing the delta phase, while CDRX characterized by SGPR occurs in the austenite phase as an auxiliary nucleation mechanism.