GH2907合金热变形本构方程

Isothermal compression test of GH2907 superalloy was conducted by Gleeble-3500 thermal simulator, the deformation behavior of the superalloy was studied at the forming temperature of 950~1100 ºC and the strain rate of 0.01~10 s^-1. The results show that the flow stress of the superalloy decreases significantly with the forming temperature increasing or the strain rate decreasing. The deformation activation energy (Q) of the superalloy was calculated to be 463.043 kJ•mol^-1 by Arrhenius equation and Zener-Hollomon. Furthermore, the stress-strain curve of the superalloy has obvious dynamic recrystallization (DRX) characteristics, and the strain, forming temperature and strain rate all have significant effect on the DRX volume fraction. At the same strain, the DRX volume fraction of the superalloy increases significantly as the forming temperature increases or the strain rate decreases. Based on the stress-dislocation relationship and DRX kinetics, the physically-type constitutive models of the two stages including work hardening-dynamic recovery and dynamic recrystallization were established to describe the relationships between flow stress and hot working parameters. According to the error analysis, the correlation coefficient R is 0.987 and the prediction value is in good agreement with the experimental. Therefore it can be used to accurately describe the thermal deformation behavior of GH2907 superalloy.