Abstract:

Effects of various iron stoichiometry on diffusion of hydrogen in disordered and ordered Ni₃Fe alloys are studied by cathodic charging with hydrogen. The elongation increases and intergranular (IG) depth decreases with increasing iron content respectively for disordered and ordered Ni₃Fe alloys precharged hydrogen under the same precharging condition. Based on a time-lag method, as the iron contents for the disordered and ordered Ni₃Fe alloys is increased with the same pre-charging, the apparent diffusion coefficient of hydrogen and the apparent activation energy of hydrogen diffusion decrease. Diffusion coefficient of hydrogen in disordered Ni₃Fe alloy is greater than that in ordered Ni₃Fe alloy under the same condition.

Key words: Ni₃Fe alloy; hydrogen embrittlement; Fe content; hydrogen diffusion