Mechanical characterization of EUROFER97 irradiated (0.32 dpa, 300 °C)

The reduced-activation ferritic martensitic steel EUROFER97 (9CrWVTa) is presently considered for the Breeding Blankets Modules of DEMO and for the Test Blankets Modules developed in the EU. In this work, the first results on neutron irradiated EUROFER97 are reported. Mechanical specimens machined from a forged bar (heat no. E83699) have been irradiated in the BR2 reactor at 300 °C up to a fluence of 2.14×1020 n/cm2 (E>1 MeV). Tensile, impact and fracture toughness test results have been obtained from the irradiated samples, allowing to assess the consequences of neutron exposure on the mechanical strength (hardening) and toughness properties (embrittlement) of the material, after comparison with data available for the unirradiated condition. The effects of irradiation on EUROFER97 have been compared with those observed on other RAFM steels (F82H in particular), under comparable irradiation conditions. Irradiation hardening was found to be higher than for other RAFM steels (including F82H) in terms of mechanical strength increase, whereas ductility is practically unaffected. As far as irradiation embrittlement (shift of Charpy-based DBTT) is concerned, EUROFER97 appears to perform slightly better than the most recent RAFM steels.