Mechanism of reversible effect of hydrogen on mechanical properties of steel

By analyzing the experiment data on the influence of gaseous hydrogen on physicomechanical properties of steers, we consider the mechanism of reversible hydrogen embrittlement, focus our attention on the processes of surface interaction, and explain the surface-active properties of hydrogen. The low solubility, high mobility, and affinity to metals characterize hydrogen as the most efficient surface-active element with respect to metals. We propose to consider the ability of hydrogen to concentrate in certain microvolumes of metal as the main point for explanation of the mechanism of reversible hydrogen embrittlement. The actual behavior of the material is determined by hydrogen localized in defects of the structure, but its total concentration cannot characterize the degree of danger of hydrogen degradation. Depending on the deformation conditions, the interaction of a metal with hydrogen either promotes plastic flow or leads to selective fracture.