Hydrogen diffusion in low alloy steels under cyclic loading

The aim of this work is to analyze hydrogen transport in a low alloy steel by applying the electrochem- ical 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 dif- fusivity takes place, along with a marked and instantane- ous reduction of diffusing hydrogen in the lattice and an increase in hydrogen solubility. An effect on the permea- tion 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