Assessment of irradiation embrittlement of the Eurofer97 steel after 590 MeV proton irradiation

The irradiation hardening of the Eurofer97 steel following 590 MeV proton irradiations was determined at three different irradiation temperatures, 50 °C, 250 °C and 350 °C, and various doses up to about 1.3 displacement per atom. The dose and temperature dependence of the irradiation hardening was characterized by a linear relationship between the irradiation hardening and the square root of the dose as: Δσ0.2 = k(T) dpa1/2. Mini pre-cracked bend bar (1 × 1 × 16 mm3) were also tested in the lower ductile to brittle transition region before and after irradiation at 300 °C and 0.5 dpa. The effective fracture toughness-temperature curves, Ke(T), were indexed on an absolute temperature scale at T0 for Ke = 100 MPa m1/2 for both the unirradiated and irradiated condition. The irradiation-induced temperature shift ΔT0 of the Ke(T) curves yielded a coefficient C0, defined as C0 = ΔT0/Δσ0.2, of about 0.53. For these low doses, helium effects could not be identified on the fracture properties.