Effect of hydrogen ion irradiation on the mechanical properties of thermally aged Z3CN20.09M duplex stainless steel

In order to investigate the synergistic effect of thermal aging and hydrogen, Z3CN20.09M duplex stainless steels (DSS) were thermal aged at 400 °C and then the irradiated by hydrogen ions. Due to the segregation of the Fe and Cr elements induced by spinodal decomposition, the nanohardness of the ferrite phase increased after thermal aging process. The irradiation effects by hydrogen ion could further increase the nanohardness of the damage region. But the {011} slip system structures formed by the irradiation significantly suppressed the hardening effects of the ions irradiation induced dislocations and spinodal decomposition induced element segregation. During the in-situ transmission electron microscopy (TEM) tensile process, severe deformation occurred and extended along a slip band that ran diagonally across the entire sample region. At last, a cracking formed at the deformation center area and propagated along the crack tip towards the irradiation damage side, ultimately leading to the sample fracture. This study serves as a valuable reference for improving the properties of Z3CN20.09M DSS utilized in nuclear plants. •Z3CN20.09M steels were thermally aged and irradiated by H ions.•{011} slip system structures were formed by the H ions irradiation.•Hydrogen can suppress the hardening effects induced by spinodal decomposition.