Investigation of hydrogen diffusion and trapping behavior under tensile stresses in a container steel

Hydrogen embrittlement is the interaction between stress and hydrogen existing in materials or absorbed from environment. Exploring the hydrogen diffusion behavior under action of static tensile stress is necessary to understand the mechanisms of hydrogen embrittlement which happens before yielding. In this work, a new method was utilized to do research on hydrogen diffusion behavior of a container steel through hydrogen permeation tests under three static stress points, which can be realized by combining slow strain rate machine and Devanathan-Stachurski cells. Results demonstrated that with the increasing of static stress within elasticity, the hydrogen diffusion coefficient increases, the density of irreversible traps (M7C3 and Cu-rich particles) decreases, and some of irreversible traps would transform to reversible traps at the same time. Irreversible hydrogen traps have been believed to improve resistance to hydrogen embrittlement, which had been studied here that is not reliable for application of those structural parts bearing stress. (C) 2019 Published by Elsevier B.V.