Evaluation of hydrogen stresses in metal and redistribution of hydrogen around crack-like defects

Abstract

The problem of the mutual influence between diffusion processes and the stress field in metal–hydrogen systems is generally formulated. Thermodynamic analysis of the stress–strain state of an elastic body under conditions of changes in concentration of available hydrogen, is performed. This formed a basis for estimation of the relative expansion of hydrogenated metal. Forces in the metal, caused by hydrogen effect, have been found to have the gradient character. The key equations for evaluation of the interaction of stresses and hydrogen concentration are constructed accounting hydrogen-induced stresses. In the quasi-stationary case for low-variable stresses the system of such equations is reduced to one concentration equation. Its solution is can be constructed in a closed form. As a result, the variation of stresses, depending on the depth of hydrogen penetration from the surface, is calculated. The dependence of hydrogen concentration and distribution in a strip vs. time laps has been determined.The proposed approach allows to estimate the redistribution of hydrogen in metal around the circular, elliptical and crack-like stress concentrators under external loading.