Novel Characterization of Deformation Mechanisms in a Ni-base Superalloy Using HAADF Imaging and Atomic Ordering Analysis

Ni-base superalloy 718 is a prominent material used for disk components in modern turbine engines. Though there is an extensive database of processing/property relationships that has been developed over its decades of use, there is little consensus on the deformation mechanisms present in 718 over its usable temperature range [1]. The asymmetry of the D022 γ′′ strengthening phase has been shown to cause numerous deformation modes in literature, including microtwinning, stacking fault formation, and the cooperative motion of like-signed 1/2<110> dislocations [1,2] in overaged samples. In this work, the post-deformation dislocation structure are analyzed in order to inform the creation of mechanisticallyaccurate yield strength models in commercially-relevant materials.