Radiation resistance and thermal creep of ODS ferritic steels

Oxide dispersion strengthened (ODS) ferritic steels containing 0.38–0.39 wt% Y2O3 have been produced by mechanical alloying. After thermo-mechanical treatment, the structure of ODS steels includes polygonized extended grains and a great number (to ∼1016–1017 cm−3) of ultrafine complex yttrium oxides ∼2–3 nm in diameter. Irradiation by fast neutrons to 4.5×1026 n/m2 (340 K) and 1.5×1022 n/m2 (77 K) leads to strengthening and plasticity decreasing in ODS alloys. The advantages of ODS ferritic steels in creep resistance and strength against ferritic-martensitic steel 12Cr–2Mo–Nb–B–V and austenitic steel 16Cr–15Ni–3Mo–Ti–V display obviously when creep rate is approximately 10−2 h−1 and fracture time is longer than 1000 h.