Research on constitutive equations and hot working maps of Incoloy028 alloy based on hot compression tests

Hot deformation behavior of Incoloye028 alloy was investigated by conducting hot compression tests on Gleeble-3800 simulator in the temperature range of 1223–1473 K and the strain rate range of 0.1–50 s−1. True stress–true strain curves showed that the flow stress increases with the decrease of deformation temperature and the increase of strain rate. The constitutive equations of Incoloy028 alloy were obtained by introducing Zener–Hollomom parameter, the flow behavior can be described by the hyperbolic sine function and the activation energy changes with strain rate and temperature significantly. The hot working maps of Incoloy028 alloy were proposed on basis of dynamic materials model. The hot working maps for different strains indicated that there were two instability zones, one zone is in the temperatures range of 1423–1473 K and strain rate range of 0.1–50 s−1, and another zone is in the temperature range of 1223–1423 K and strain rate range of 0.6–1 s−1. The reasonable hot working temperature range is 1423–1473 K when strain rate is more than 50 s−1.