Deformation and recrystallization behavior of the new Ni-Co based superalloy ingot material prepared by electron beam smelting layered solidification

The hot deformation behavior of a Ni-Co based superalloy prepared by electron beam smelting layered solidification (EBSL-Ni-Co superalloy) was studied by hot compression tests under the temperature range of 1070-1180 degrees C and the strain rate range of 0.001-1 s-1 with a true strain of 0.693. The results show that the flow stress increases with the increase of strain rate and the decrease of deformation temperature, and the friction effect and adiabatic heating effect make the measured value of material flow stress higher than the real value. The hyperbolic sine Arrhenius equation was developed based on the gamma' phase solution tem-perature, and the plastic flow stress model of the EBSL-Ni-Co superalloy was established. The deformation activation energies of the alloy in the gamma + gamma ' dual-phase and gamma single-phase regions were 621.6 kJ/mol and 368.6 kJ/mol, respectively. The processing map of the superalloy was constructed based on the dynamic material model (DMM). Combined with the variation of microstructure, the optimum hot deformation processing conditions of the superalloy were determined. The increase of strain rate and the decrease of deformation temperature, the proportion of low-angle grain boundaries (LAGBs), and the reduction of re -crystallization. Additionally, the hot deformation behavior of the EBSL-Ni-Co superalloy was found to be greatly influenced by the coarsening of gamma' phase solution temperature.(c) 2022 Elsevier B.V. All rights reserved.