Critical strain and models of dynamic recrystallization for FGH96 superalloy during two-pass hot deformation

The dynamic recrystallization critical strain of FGH96 alloy was investigated by isothermal two-pass hot deformation compression tests in the temperature range of 1050–1125 °C and strain rates ranging 0.001–0.1 s−1 with the deformation of 45+45% on a Gleeble-1500 thermo-simulation machine. Two dynamic recrystallization models were established. Degree of recrystallization between the metallographic microstructure and the result of the recrystallization model was contrasted. The results show that dynamic recrystallization occurs in the two-pass hot deformation. The deformation behavior of the second-pass is influenced by the recrystallization and the residual strain of the first-pass. The critical strain is obviously influenced by temperature and strain rate. The critical strain of the second-pass is smaller than that of the first-pass. The dynamic recrystallization models between the first-pass and the second-pass hot deformation are different. The volume of recrystallization calculated by the dynamic recrystallization model is in good agreement with the metallographic microstructure.