Tensile tests on MANET II steel in circulating Pb–Bi eutectic

Off-beam tensile tests have been performed on MANET II steel in the eutectic Pb–55.5Bi (LBE) and Ar during commissioning of the LiSoR loop, an experimental liquid metal loop, which was developed to investigate the influence of Pb–Bi on possible structural materials under static load and irradiation. Test temperatures were 180–300 °C. MANET II (11% CrMoVNb steel) exhibits good swelling and creep resistance behaviour under irradiation up to around 500 °C. Good corrosion resistance of this material is expected due to the absence of the element Ni in the steel matrix which has a high solubility in LBE. All specimens showed a ductile fracture in Ar. In LBE a loss of ductility was observed at the test temperatures of 250 and 300 °C in comparison to the Ar samples. SEM analysis of the fracture surface of these specimens revealed a mixed mode, i.e. dimple and brittle fracture and penetration of Pb–Bi along the grain boundaries, which is a typical finding for liquid metal embrittlement.