HYDROGEN PERMEATION AND DIFFUSION IN ALLOY INCOLOY 903

Permeability and diffusivity of hydrogen in Fe-Ni-Co based superalloy lncoloy 903 weremeasured over the temperature range of 220 to 420℃ using a gaseous permeation technique.The effect of strengthening phase γ' precipitated after being aged on the hydrogenpermeation and diffusion was investigated.It was indicated that the permeability anddiffusivity of hydrogen in the alloy hardly depend on heat treatment condition and are not af-fected by γ' phase precipitated after being aged.The relationships between the permeabilityand diffusivity of hydrogen and the temperature can be respectively expressed asΦ=9.36×10~(-5)exp-54.20(kJ/mol)/RT]mol/m·s·MPa~(1/2)andD=4.24×10~(-7)exp-49.07(kJ/mol)/RT]m~2/s.