Hydrogen diffusion in low alloy steels under cyclic loading

Abstract

Abstract The aim of this work is to analyze hydrogen transport in a low alloy steel by applying the electrochemical permeation technique to matrices subject to cyclic loading conditions, up to the yield strength and beyond this limit. The results indicate that, with an increase in the applied maximum stress, a decrease in the apparent diffusivity takes place, along with a marked and instantaneous reduction of diffusing hydrogen in the lattice and an increase in hydrogen solubility. An effect on the permeation current was observed, together with a variation of hydrogen diffusion kinetics ascribable to the activation on new trapping sites, with an appreciable effect under cyclic loading already at 55% of the yield limit, which becomes more relevant in the plastic domain.