Hydrogen permeation in plastically deformed steel membranes

Abstract

We study the influence of plastic deformation on the electrochemical permeability of hydrogen. For this purpose, membrane specimens of FeE690T steel were deformed in the cold state by rolling or tension, and the diffusion of hydrogen in these specimens was measured by the classical Devanathan-Stachursky technique. The effective diffusion coefficients are determined according to the time dependences of the intensity of hydrogen flow from the back side of the membrane. They are characterized by the well-pronounced dependence on the level of strain. Moreover, the diffusion of hydrogen is simulated by taking into account the phenomenon of seizure of hydrogen atoms by traps formed in the presence of plastic strains. The linear diffusion equation is used to compute the time dependence of permeation of hydrogen for various densities of the traps. The effective coefficients of hydrogen diffusion are determined from the permeation curves. The accumulated results are in good agreement with the experimental data.