High temperature deformation behavior of hot isostatically pressed P/M FGH4096 superalloy

The hot deformation behavior of hot isostatically pressed (HIPd) P/M superalloy FGH4096 has been characterized by isothermal compression testing in the temperature range of 1050-1140 degrees C and strain rate range of 0.002-1.0 s(-1). The apparent activation energy of deformation was calculated to be 418 kJ/mol, and constitutive equation that described the flow stress as a function of the strain rate and deformation temperature was proposed for high temperature deformation of the alloy. The processing map was calculated to evaluate the efficiency of the forging process in the temperatures and strain rates investigated and to recognize the instability regimes. It was found that the strain has no significant effect on the processing maps. The optimum processing conditions were in the strain rates of around 0.01-0.2 s(-1) and temperatures of 1080-1110 degrees C, the efficiencies are higher compared to other stable regimes. The DRX occurs at the temperatures of 1050-1130 degrees C and strain rate range 0.005-0.2 s(-1). At the processed temperature of 1080 degrees C, lower than dissolution temperature of gamma' phase about 30 degrees C, undissolved gamma' phase particles were contributed to restricting the coarsening of complete recrystallized grains. Plasticity instability was expected in the regime of strain rate higher than 0.4s(-1) and temperature range of 1090-1130 degrees C. Crown Copyright (C) 2009 Published by Elsevier B.V. All rights reserved.