A novel method based on composite effects for evaluating the hydrogen embrittlement of steels with low hydrogen diffusion coefficients

The effect of hydrogen on mechanical properties of a twinning-induced plasticity austenitic steel was investigated by slow strain rate tensile tests and scanning electron microscopy after various hydrogen pre-charging conditions. A new method for evaluating hydrogen embrittlement of materials with low hydrogen diffusion coefficient has been proposed. Materials with low hydrogen diffusion coefficients can be regarded as composite materials after pre-charging, i.e., a hydrogen-rich brittle region and a hydrogen-lean ductile region. Based on the rule of mixtures, the influence of the hydrogen on the mechanical properties can be reflected by the contribution of the brittle zone to the overall mechanical properties, which is more realistic and universal compared to the characterization of the mechanical property loss by hydrogen content. This helps to simplify the selection of materials resistant to hydrogen embrittlement by directly comparison linear loss of mechanical properties when the “average” hydrogen content of the brittle region is similar.