Review on hydrogen embrittlement behavior of Ni-based superalloys

Hydrogen embrittlement is a common damage phenomenon in high-strength alloys, which involves multiple phenomena, such as the dissolution, diffusion, redistribution of hydrogen, and the interaction of hydrogen with vacancies, dislocations, grain boundaries, and other phase interfaces. To explain hydrogen embrittlement, hydrogen diffusion, and characteristic methods were investigated and various mechanisms have been proposed, including the hydrogen enhanced decohesion (HEDE) mechanism, the hydrogen enhanced local plasticity (HELP) mechanism, and the hydrogen enhanced strain-induced vacancy (HESIV) mechanism. The advantages and limitations of current hydrogen embrittlement mechanisms and prevention methods were discussed. Furthermore, to reduce the risk of hydrogen embrittlement in engineering structural materials during service, measures such as surface treatments and optimization of alloy microstructures have been suggested.