摘要
A ferritic steel ( 21 4 Cr-1 Mo) was heat-treated to produce three distinct microstructural regions; upper bainite, lower bainite and ferrite. The irradiation response of these different microstructures at 500°C to 14 MeV nickel-ion-irradiation was studied under identical conditions. Damage levels ranged from 80 dpa at the 1 μm depth to 350 dpa at the peak damage depth at 2.1 μm. Irradiated samples were studied in cross section using TEM/AEM thin foil techniques supplemented by precipitate extraction methods. The irradiation drastically changed the type of precipitate in the bainite regions from M 3 C carbides to radiation-enhanced M 2 C and M 7 C 3 carbides, and the radiation-induced χ phase was also observed. The radiation-induced G phase was the only precipitate type formed in the initial ferrite structure. No voids were observed up to 350 dpa in any of the three microstructures unless preinjected helium was present. An average swelling of 0.2% was measured after a dose of 100 dpa in the sample preimplanted to 100 at.ppm helium. © 1986.