Hot deformation characteristics and processing map of nickel-based C276 superalloy

The hot compression tests for the nickel-based C276 superalloy were carried out on a Gleeble-1500D simulator in the temperature range of 950-1250 degrees C with the strain rate range of 0.01-10.0 s(-1). The high-temperature deformation behaviors of C276 superalloy were analyzed based on the true stress-true strain curves. The results show that during the hot deformation process of C276 superalloy, under the same temperature, the flow stress rises with the increasing of strain rate. At the same strain rate, the flow stress decreases with the increasing of the temperature. As the strain rate is less than 1.0 s(-1), there exist peak stress and steady flow stress, and only peak stress appears at 10.0 s(-1). The processing maps of C276 superalloy in different strains were constructed according to DMM model. A small area where the power dissipation efficiency is higher than that in others areas exists in the maps. In this area the deformation temperature and strain rate is 1050-1150 degrees C, 0.01-0.1 s(-1), and the fully dynamic recrystallization has been completed. There exists a small area of rheological instability in the processing map where the temperature is low, while the strain rate is high, and the dynamic recrystallization grains are distributed along the adiabatic shearing zone. According to the microstructure evolution and the processing maps of the C276 superalloy, its suitable processing condition can be summed up as that the temperature range is between 1050 degrees C and 1150 degrees C, and the strain rate range is between 0.01 s(-1) and 0.1 s(-1). (C) 2014 Elsevier B.V. All rights reserved.