Interactions between dislocations and γ/γ' interfaces in superalloys

“In situ” transmission electron microscopy observations of the dislocation motion at vicinity of the γ/γ' interfaces in a Ni-base superalloy have been performed. They allow to identify the elemental mechanisms, under stress and at different temperatures, of the deformation propagation across the interfaces. It is shown that some of the mechanisms already analyzed in the literature occur. Moreover, new processes are revealed such as the formation of small dislocation pile-ups on the γ/γ' interfaces. Such a configuration, which increases the local stress, favors the overcoming of the interface.