Hot Deformation Behavior of AA-FGH720Li Superalloy

The hot deformation behavior of FGH720Li superalloy was investigated by hot compressive tests on Gleeble-1500D thermal simulation test machine in different temperatures and strain rates. The true stress-strain curves were obtained, and based on the deformation data, the constitutive equation of FGH720Li superalloy was built. The Deformation Active Energy of FGH720Li was determined to be Q=787.6KJ/mol. The main deformation modes were dislocation glide and twinning. At the beginning of the deformation, a large number of dislocations generated, glided and scrambled in the alloy, then entwisted to form dislocation cells, which were the recrystallization nucleus. At the later period of the deformation, the dislocation would rotate to easy glide direction through twinning, inducing that the deformation of the alloy ensued. At the same time, the deformation had significant effect on grain refinement and the crushed of the primary particle boundary.