Hot Deformation Behavior and Hot Processing Map of GH2907 Superalloy

The hot deformation behavior of GH2907 superalloy at deformation temperature of 950~1100℃, strain rates of 0.01~10 s^-1 and deformation degree of 60% was studied by thermal simulation compression experiments. The results show that flow stress decreases significantly as the deformation temperature increases or strain rate decreases; according to the Arrhenius equation and the Zener-Hollomon parameter, the thermal deformation activation energy (Q) can be calculated, and the hot deformation constitutive equation of GH2907 superalloy is also established. On the basis of the dynamic material model, the power dissipation map under different strains of the GH2907 superalloy is obtained. The region with higher power dissipation efficiency (η) is located at the temperature of 1050~1100℃ and strain rates of 0.01~0.03 s^-1, and the microstructure dynamic recrystallization phenomenon also occurs in the deformation region; based on the Prasad instability criterion, the hot processing map of GH2907 superalloy under different strains is drawn. The rheological instability zone is located in the high temperature range of 970~1100℃ and high strain rate range of 0.6~10 s^-1. In addition, the dynamic recrystallized grains are distributed along the adiabatic shear band and flow locally in this deformation region. According to the hot processing map and microstructure analysis of GH2907 superalloy, the suitable processing area is in the temperature range of 1050~1100℃ and strain rates of 0.01~0.03 s^-1.