Effects of tensile stress/strain on hydrogen permeation and adsorption behaviours

Purpose The purpose of this study is to develop the hydrogen permeation and hydrogen adsorption characteristics under different tensile stresses/strains. Design/methodology/approach Hydrogen diffusion, hydrogen adsorption and density functional theories were used to investigate the effects of tensile stress on the ingress behaviour of hydrogen. Findings Tensile stress/strain facilitated atomic bond relaxation and dislocation multiplication, resulting in a negative shift in the corrosion potential. Simultaneously, stress–defect interactions and dislocation multiplication induced by tensile stress/strain resulted in a decreased effective hydrogen diffusion coefficient. More importantly, tensile stress significantly enhanced surface hydrogen adsorption by increasing surface energy and introducing dislocation-induced adsorption sites. Furthermore, stress–defect interactions and dislocation multiplication suppressed hydrogen desorption and hindered subsurface hydrogen escape. In addition, strain reduced the hydrogen barrier energy, and dislocation multiplication provided fast diffusion channels, synergistically accelerating the hydrogen penetration into subsurface. These mechanisms collectively increased the surface coverage and hydrogen content. Originality/value The effects of tensile stress/strain on hydrogen permeation and adsorption behaviours were systematically analyzed.