Evolution of the mechanical properties and microstructure of ferritic–martensitic steels irradiated in the BOR-60 reactor

The effect of neutron irradiation on mechanical properties of low-activation ferritic–martensitic (FM) steels 0.1C–9Cr–1W, V, Ta, B and 0.1C–12Cr–2W, V, Ti, B is studied under tension at temperatures of 330–540 °C and doses of 50 dpa. Steel 0.1C–13Cr–Mo, V, Nb, B was chosen for comparison. At irradiation temperatures of 330–340 °C, the radiation hardening of steel with 9%Cr achieves saturation at a dose of 10 dpa. In this case as compared to steels with 12%Cr, the fracture surface is characterized as ductile without cleavage traces. At irradiation temperatures higher than 420 °C, there is no difference in the behavior of the materials under investigation. The data on radiation creep obtained by direct measurement and from the profilometry data satisfy a model ε̄/σ̄=B0+DṠ, when B0 and D have the values typical for steels of FM type.