Journal of Electron Microscopy 51:S239-S243 (2002)
© 2002 Oxford University Press
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Microstructural development and swelling behaviour of F82H steel irradiated by dual ion beams
Department of Materials Science, Tokai Research Establishment, JAERI, Tokai-mura, Ibaraki, 319-1195, Japan
To whom correspondence should be addressed. E-mail: wakai{at}realab01.tokai.jaeri.go.jp
Abstract Microstrucutral development and swelling behaviour of F82H (Fe-8Cr-2W-0.2V-0.04Ta-0.1C) steels irradiated at 435°C by dual beams of 10.5 MeV Fe3+ and 1.05 MeV He+ ions to 50 displacement per atoms (dpa) were investigated. The specimens used were F82H-std steel tempered at 750°C for 60 min and 40% cold-worked F82H-std (F82H + CW). The irradiation of helium atoms was controlled to implant in depths from 0.5 to 1.3 µm using an energy degrader with aluminium foil. The ratio of helium concentration to dpa was about 10 appmHe dpa-1. Many small bubbles of 29 nm in F82H-std and 26 nm in F82H + CW were observed between about 0.1 and 1.8 µm from the surface. Swelling in F82H-std and F82H + CW was 0.1 and 0.06%, respectively, and was suppressed in cold-worked materials. Some micro-polycrystallines in the F82H-std were formed in only the irradiated range by the irradiation, and many were formed in F82H + CW steel. The sizes of the micro-polycrystallines in F82H-std and F82H + CW steels were about 0.5 and 0.3 µm, respectively.
Keywords F82H, ferritic steel, dual beam, cavity, swelling, recrystallization