Simultaneous Enhancement of Tensile Properties and Hydrogen Embrittlement Resistance in Cu-bearing Austenitic Stainless Steel

Austenitic stainless steels have been utilized in hydrogen (H) facilities for their excellent mechanical properties, corrosion resistance, and resistance to hydrogen embrittlement, but their low yield strength and high alloying costs hinder their competitiveness in steel industries. This study investigated the effects of Cu-rich precipitates on tensile properties and hydrogen embrittlement resistance in Cu-bearing Fe–Cr-Ni-based austenitic stainless steel with varying grain sizes. Tensile properties significantly improved after aging at 700 °C due to the formation of Cu-rich precipitates and subsequent changes in deformation mechanisms. The formation of Cu-rich precipitates decreased solute Cu in the austenite matrix, alleviating the stress localization to improve ductility of the steel. Cu-rich precipitates enhanced hydrogen embrittlement resistance by interfering with the diffusion of H, thereby reducing the amount of desorbed H and preventing H segregation during deformation. The aged specimen subsequently exhibited superior tensile properties and hydrogen embrittlement resistance compared to the annealed specimens, demonstrating the effectiveness of precipitation strategies.