Plastic deformation behavior of spray formed superalloy FGH100

Abstract

Hot compression tests of hot isostatic pressed (HIPped) spray formed (SF) nickel-base superalloy were carried out in the temperature range of 1050–1150°C at strain rates of 0.001–1s−1, between 10–70% of engineering strain, using a Gleeble-1500 thermal simulator. Thereafter, the flow curve was developed and the constitutive equation of flow stress during hot deformation was established. The results show that the flow stress decreases by increasing deformation temperature and decreasing strain rate. Processing maps were developed based on the data obtained using the principles of dynamic materials modeling. The microstructure of deformed samples was characterized using optical and electron microscopy. The processing maps exhibit the stability domain at the temperatures of 1140–1150°C and strain rate of 0.01s−1, with a peak efficiency of approximately 50%. High deformation temperature and high strain rate are conducive to the occurrence of dynamic recrystallization. The activation energy of the new Ni-Cr-Co based SF superalloy FGH100 was found to be 866.7kJ/mol. Besides, the experimental results verify the hyperbolic sine model including strain variable, reflecting the changing law of flow stress during the hot deformation process.