Microstructure Evolution of Delta-Processed GH4169 Alloy during Hot Deformation

The hot compressive deformation experiments were conducted on the delta-processed GH4169 alloy at the deformation temperatures of 900-1 060 ℃ and strain rates of 0.001-0.500 s^-1. The effects of deformation temperature, strain rate and strain on the microstructure and the morphology and evolution of δ phase were studied and the evolution mechanism of microstructure was analyzed. The results show that a large number of plate-like or long-needle-like δ phase distributed in the microstructure of the delta-processed alloy. During the hot compressive deformation, with the increase of strain, the bending, kinking and spheroidization of the δ phase occured due to the combined effects of deformation and dissolution breakages. With the deformation temperature increasing or the strain rate decreasing, the content of δ phase decreased, while the grain size and the volume fraction of dynamic recrystallization increased.