Dynamic recrystallization behavior of a newly developed Ni-Fe based superalloy during hot deformation

Abstract

The dynamic recrystallization (DRX) behavior of a newly developed Ni-Fe based superalloy was investigated by isothermal compression tests performed at a wide temperature range of 950 to 1200 °C with a strain rate range from 0.01 to 10 s−1 under a true strain of 0.916. The electron backscatter diffraction (EBSD) technique was employed to investigate the effect of strain rate and temperature on the microstructure evolution. The results revealed that the size and volume fraction of DRX grains increased with increasing the temperature. The volume fraction of DRX grains first decreased and then increased with increasing the strain rate during the hot deformation. The preferred orientation of the overall grains changed from <001>//CD to <110>//CD with increasing the strain rate during the deformation at 950 °C, while the preferred orientation of overall grains consistently maintained as <001>//CD during the deformation at 1200 °C. DDRX was the dominant mechanism during the deformation, while CDRX was proved to be an assistant mechanism and was promoted with increasing the strain rate.