Determining irradiation damage and recovery by instrumented indentation in RAFM steel

The mechanical behavior of specific reduced-activation ferritic-martensitic steels (RAFM), designed for fusion applications, is investigated in the present study. Eurofer97 and F82H-mod specimens have been neutron-irradiated in the High Flux Reactor at Petten (HFR) up to a dose of 15 dpa at 250–450 °C. An indentation method [1], making use of a data post-analysis program based on neural networks, has been employed to identify tensile properties by multistage indents. The significant irradiation-induced hardening effect present at 15 dpa in the range of 250–350 °C could be observed in Vickers hardness and in the calculated material’s strength parameters, the influence of the pre-irradiation heat treatment could be identified. Post-irradiation annealing treatments have been realized at 500 °C and 550 °C and leads to a partial recovery of the irradiation damage.