Hydrogen induced crack initiation in a nickel-based superalloy was studied via in-situ Scanning Electron Microscopy observation under slow strain rate loading. Direct evidence has been obtained of crack initiation and propagation along dislocation slip bands leading to sample fracture. Post-mortem microstructural analysis showed that hydrogen induced cracking and separation along dislocation slip bands, which are along {111}γ crystallographic planes with the highest Schmid factor, leads to the formation of the typical slip-trace-like features on the quasi-cleavage surface.
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