Hydrogen-promoted heterogeneous plastic strain and associated hardening effect in polycrystalline nickel under uniaxial tension

We deformed polycrystalline nickel and quantitatively revealed that hydrogen promotes the grain-scale plastic deformation heterogeneity by assisting generation and accumulation of geometrically necessary dislocations within grain interiors and at grain boundaries. Bauschinger tensile tests also confirmed that hydrogen enhances hetero-deformation induced stress, which is the global result of hydrogen-promoted heterogeneous plastic deformation in the entire samples.