Influence of hydrogen on material behaviour of high nitrogen austenitic stainless steel

Alloying austenitic stainless steels with nitrogen up to a concentration of 1 wt-% improves yield strength, tensile strength, and ductility. Hydrogen charging enhances the yield strength but reduces both the tensile strength and remarkable the ductility with increasing hydrogen content. These effects are pronounced at higher nitrogen concentrations. The loss of the mechanical properties as well as increasing hydrogen solubility and decreasing diffusivity is related to a high reversible lattice dilatation caused by an attractive interstitial interaction between nitrogen and hydrogen atoms.