Analysis of tensile and fracture toughness results on irradiated molybdenum alloys, TZM and Mo–5%Re

Due to their good resistance at high temperature, good thermal conductivity and swelling resistance, molybdenum alloys are amongst the candidates for divertor structural materials. However, little is known about their tensile and fracture toughness behaviour, in particular after irradiation-induced embrittlement. This paper aims to investigate the tensile and fracture toughness properties of two molybdenum alloys, namely TZM and Mo–5%Re. Tensile and compact tension specimens were irradiated in the BR2 reactor at 40°C and 450°C up to a fast neutron fluence of 3.5×1020 n/cm2 (0.2 dpa). Tests were performed on both precracked and notched specimens. Results show a drastic decrease of the ductility due to irradiation, but only a slight decrease of the fracture toughness in the lower shelf domain.