Synergy effect of LBE and hydrogenated helium on resistance to LME of T91 steel grade

The aim of this paper is to determine the influence of the environment on the resistance to LME of the T91 steel/LBE system. First, we recall that a few hours of exposure to LBE under flowing hydrogenated helium (He–4%H2) is sufficient to modify the corrosion resistance and wettability of T91 steel, once the temperature attains 350 °C. This result is consistent with a degradation of the protectiveness of the surface oxide film with increasing temperature from 150 to 350 °C, in present experimental conditions. Then, the tensile properties of T91 steel are studied as function of the temperature and cover gas. A reduction in strength and ductility of T91 steel is found, passing through a maximum at the temperature of 350 °C under flowing He–4%H2, and suggesting a synergy effect of LBE and hydrogenated helium.