Influence of hydrogen on electrochemical behavior of Ni-based superalloy 718

Abstract

Numerous studies have shown that Ni-based superalloy 718 may be sensitive to hydrogen embrittlement and have highlighted the dominant roles played by the hydrogen solubility and the hydrogen trapping. Samples were hydrogenated by cathodic polarization in molten salts under different conditions ta vary the diffusible hydrogen content and ta saturate the different hydrogen traps present in the microstructure strengthened by precipitation. Open circuit potential and galvanic coupling measurements were conducted in order to char acterize the effect of diffusible and trapped hydrogen on electrochemical behavior and to discuss the possibility of galvanic coupling between zones with different hydrogen contents. Hydrogen embrittlement Electrochemistry Galvanic coupling

Effect of electrochemical charging on the hydrogen embrittlement susceptibility of alloy 718

“…6(b4)) [8,28,30]. Quasi-cleavage is a commonly reported fracture feature in the hydrogenated precipitation-hardened Alloy 718 [9,29,76,77]. Hydrogen-induced cracking along dislocation slip bands (DSBs), particularly at nonparallel DSBs intersections near the surface [8,9,76], has been claimed to be the reason for the observed quasi-cleavage feature.…”