Permeation of hydrogen in Ni-based superalloy CMSX-4 Original Research Article

Permeation of hydrogen in CMSX-4 superalloy single crystals was studied by the volumetric method in the temperature interval from 573 to 1173 K. The measurements were carried out with two purity grades of hydrogen and for various sample thicknesses to estimate the influence of surface effects upon the permeation rate. The effect of phase transformation in the γ′ particles upon permeation rate was detected.