A novel dynamic recrystallization kinetics model based on particle-stimulated nucleation of the HEXed FGH4113A alloy during hot deformation

The impact of deformation temperature (1050-1140 degrees C) and strain rate (1-0.001 s_ 1) on the microstructure evolution and dynamic recrystallization (DRX) mechanisms of the HEXed FGH4113A alloy are investigated. Two primary DRX mechanisms, namely discontinuous dynamic recrystallization (DDRX) and particle-stimulated nucleation (PSN), are identified. At lower temperatures and higher strain rates, the gamma' phase promotes the DRX nucleation and inhibits the grain growth. Subsequently, a fine and uniform grain structure comprising broken deformed grains and fine DRX grains are obtained. The analysis of the PSN process reveals that the gamma' phase hinders dislocation migration, and increases local dislocation density. So, DRX nucleation is promoted, which effectively reduces the activation energy required for DRX. To accurately depict DRX behavior during hot deformation of the studied alloy, a DRX kinetic model incorporating the PSN activation energy parameter (QPSN), which signifies the degree of activation energy reduction, is proposed. This model effectively represents the activation energy consumed during DRX reduction by PSN. These findings provide valuable insights for effectively controlling the microstructures of hot-deformed nickel-based powder metallurgy superalloys.