Characterization of microstructures and hot-compressive behavior of GH4169 superalloy by kinetics analysis and simulation

Mechanical performance of hot forming products is strongly related to microstructures and deformation behaviors during hot processing. Through dynamic recrystallization (DRX) kinetics analysis and simulation, evolution of microstructure and hot-compressive behavior of a solution-treated GH4169 superalloy at different deformation conditions were investigated. The DRX behavior confirmed by microstructure observations was promoted at higher temperatures and lower strain rates. No 8 phase existed at or above 1333 K deformation temperature. Flow softening extent became more significant under lower temperatures and strain rates during compression where DRX played a dominate role in the softening behavior. A dramatic yield drop occurred within the temperature range varying from 1273 K to 1333 K due to the dissolution of 8 phase and enhanced mobility of defects. The DRX kinetics model was established to calculate the volume fraction and grain size of DRX under the investigated deformation parameters. Additionally, the relationships between microstructure and deformation behavior as well as mechanical property were discussed. Excellent correlation showed a possibility of controlling microstructure and mechanical properties by selecting suitable deformation parameters. Finally, the microstructure of GH4169 superalloy in terms of grain size after hot compression was successfully predicted by finite element model integrated with the developed kinetics equations implying the excellent applicability of such model for the current study and great potential for practical applications on predicting the mechanical properties of GH4169 alloy after hot working.