Effect of Grain Size on the Hydrogen-Induced Ductility Loss of a Multicomponent CoCrFeMnNi Alloy

The effect of electrolytic hydrogenation on the mechanical properties and fracture mechanism of the multicomponent Cantor CoCrFeMnNi alloy of different characteristic grain size has been shown. It has been demonstrated that an increase in the density of grain boundaries enhances the resistance of Cantor alloy to hydrogen-induced embrittlement. The primary factors that influence the formation of brittle surface zones during hydrogen charging and subsequent uniaxial tension of hydrogen-charged samples have been identified, and the micromechanisms of their fracture have been elucidated. An increase in grain boundary density impedes the transportation of hydrogen by dislocations during plastic deformation. This is due to the limited free path of dislocations in a fine-grained structure. However, the thickness of the hydrogen-charged layer formed during hydrogen saturation is not significantly affected by the grain size.