Microstructure evolution and deformation failure mechanism of a difficult-to-deform Ni-based wrought superalloy at elevated temperature

The deformation microstructure of superalloys is highly sensitive to deformation temperature. To achieve a uniform fine-grained structure and mitigate defects, the hot deformation behavior of a Ni-based wrought superalloy was studied near the solution temperature. As the deformation temperature increased, the volume fraction of γ′ phase decreased. When the temperature reached 1200 °C, the γ′ phase dissolved completely, the grain size increased and cracks appeared in the alloy. Microstructure evolution was primarily driven by dynamic recrystallization mechanism and fracture mechanism. The results demonstrated that the dynamic recrystallization (DRX) mechanism was different under different deformation conditions. These findings provide critical theoretical guidance for optimizing hot-working processes in difficult-to-deform alloy.