Restoration of ductility in hydrogen embrittled dual-phase (DP 780) steel by the electric pulse treatment

High-strength steel components operating in a hydrogen environment are more susceptible to hydrogen embrittlement. De-hydrogenation of these components could prolong their service life, encouraging the industrial use of high-strength steel. In this study, hydrogen (H)-induced damage recovery and restoration of ductility are realized in dual-phase (DP 780) steel by the electric pulse treatment (EPT). The experimental results indicate that a complete restoration of ductility and H-induced damage recovery could be achieved with suitable electropulsing parameters in DP 780 steel. A centerline crack is observed in the fractographic examination of each hydrogenated specimen after the uniaxial tensile test. After EPT, post-necking ductility improves, and the centerline crack disappears from the fractured surface. The in-situ digital image correlation (DIC) technique is utilized during the uniaxial tensile test to measure the local strain evolution. Both uniaxial tensile necking and fracture strains are restored after EPT of hydrogenated specimens.