Tensile deformation behavior and microstructure evolution of Ni-based superalloy 617

The mechanisms of deformation were investigated in a nickel-based alloy (Inconel 617) of interest for the Intermediate Heat Exchanger (IHX) for the very high temperature reactor (VHTR). Tensile tests at 25 °C, 600 °C, 800 °C, and 950 °C were conducted in air at different strain rates. The tests were followed by electron microscopy analysis (including FE-SEM, TEM, EDX). The tensile property measurements and the metallographic examination of tested specimens allowed relating the deformation behavior with the microstructural changes in the material. The temperature and strain rate impact on the properties was assessed. The results and microstructure observations were discussed in terms of serrated flow associated with dynamic strain ageing, precipitate evolution, and softening processes due to dynamic recrystallization.