Hydrogen-enhanced compatibility constraint for intergranular failure in FCC FeNiCoCrMn high-entropy alloy

• Hydrogen induced intergranular failure in FeNiCoCrMn high-entropy alloy. • Hydrogen caused changes to evolution of deformation across length scales. • Hydrogen-dislocation interactions caused “locking-in” of evolved microstructure. • Hydrogen effects on plasticity enhanced grain boundary compatibility constraints. • Hydrogen enhanced decohesion and effects on plasticity caused intergranular failure. The fundamental mechanism of hydrogen...