Assessment of dynamic softening mechanisms in Allvac 718PlusTM by EBSD analysis

Research highlights: → EBSD investigations of hot deformed superalloy Allvac 718PlusTM. → Dynamic softening (recovery, DDRX and CDRX) in dependence on the temperature and strain rate. → At high temperature (1050 deg. C) and high strain rate (10 s-1) mainly DDRX. → At high temperature (1050 deg. C) and low strain rate (0.1 s-1) combination of DDRX, CDRX and recovery. - Abstract: The nickel-based superalloy Allvac 718PlusTM is a future candidate for turbine disc applications, as this new material combines the formability and cost advantages of Alloy 718 with the higher temperature capability of Waspaloy. Due to the strong influence of the microstructure on the final mechanical properties, a fundamental knowledge of the dynamic recrystallization mechanism of Allvac 718PlusTM is of great importance in order to develop precise microstructure evolution models for this material. Compression tests were performed at temperatures of 900 deg. C to 1050 deg. C and strain rates between 0.1 s-1 and 10 s-1. The microstructures obtained were analyzed by electron backscatter diffraction (EBSD) to evaluate the influence of the different hot forming parameters on the dynamic softening processes of Allvac 718PlusTM.