Assessment of dynamic softening mechanisms in Allvac® 718Plus™ by EBSD analysis

The nickel-based superalloy Allvac® 718Plus™ 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® 718Plus™ is of great importance in order to develop precise microstructure evolution models for this material. Compression tests were performed at temperatures of 900 °C to 1050 °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® 718Plus™.

Research highlights
► EBSD investigations of hot deformed superalloy Allvac® 718Plus™.
► Dynamic softening (recovery, DDRX and CDRX) in dependence on the temperature and strain rate.
► At high temperature (1050 °C) and high strain rate (10 s−1) mainly DDRX.
► At high temperature (1050 °C) and low strain rate (0.1 s−1) combination of DDRX, CDRX and recovery.