Hydrogen embrittlement in compositionally complex FeNiCoCrMn FCC solid solution alloy

The influence of internal hydrogen on the tensile properties of an equi-molar FeNiCoCrMn alloy results in a significant reduction of ductility, which is accompanied by a change in the fracture mode from ductile microvoid coalescence to intergranular failure. The introduction of 146.9 mass ppm of hydrogen reduced the plastic strain to failure from 0.67 in the uncharged case to 0.34 and 0.51 in hydrogen-charged specimens. The reduction in ductility and the transition in failure mode are clear indications that this alloy exhibits the classic signs of being susceptible to hydrogen embrittlement. The results are discussed in terms of the hydrogen-enhanced plasticity mechanism and its influence on hydrogen-induced intergranular failure. Furthermore, a new additional constraint that further promotes intergranular failure is introduced for the first time.