Microstructure Evolution and Dynamic Recrystallization Behavior of SLM GH3536 Superalloy During hot Deformation

GH3536 nickel-based superalloy was prepared using selective laser melting (SLM) to study its hot deformation behavior, microstructure evolution, and recrystallization mechanism during hot compression. GH3536 superalloy was hot compressed by a Gleeble-3800 hot simulation testing machine. The compression temperature was 900 degrees C similar to 1050 degrees C, and the strain rate was 0.01s(- 1)similar to 10s(- 1). The results show that the deformation conditions will significantly affect the flow stress, dislocation density, and the development of grain boundary and subgrains boundary. The dynamic recrystallization (DRX) mechanism is also easily affected by the deformation conditions and different deformation regions. The alloy has experienced work hardening (WH), dynamic recovery (DRV), and DRX in hot deformation and finally entered the steady-state rheological stage. The dynamic softening effect is more evident at a low strain rate. The temperature will strongly affect the migration of dislocations and limit the transformation from LAGB to HAGB, thus affecting the formation of grain boundaries and finally affecting the DRX mechanism. It is found that DRX is not a single process, and discontinuous dynamic recrystallization (DDRX) and continuous dynamic recrystallization (CDRX) exist at the same time. DDRX is the primary nucleation mechanism characterized by grain boundary expansion. CDRX is an auxiliary nucleation mechanism characterized by gradual rotation of subgrains, and CDRX is easier to activate at low temperatures.