STP1492: Irradiation Hardening and Microstructure Evolution of Ion-irradiated ODS Ferritic Steels

    Yutani, Kentaro
    Graduate Student, Kyoto University, Kyoto,

    Kasada, Ryuta
    Research Associates and Professor, Kyoto University, Kyoto,

    Kishimoto, Hirotatsu
    Research Associates and Professor, Kyoto University, Kyoto,

    Kimura, Akihiko
    Research Associates and Professor, Kyoto University, Kyoto,

    Pages: 8    Published: Jan 2008


    Abstract

    Irradiation hardening and microstructural change of oxide dispersion strengthened (ODS) ferritic steels were investigated by using the ion-irradiation technique. The material used for the present study was K3 (16C-2W-0.3Ti-4.6Al-0.4Y2O3) ODS ferritic steel for the application to Generation IV concept advanced reactors and fusion reactors. 6.4 MeV Fe3+ ions were used to irradiate to the K3 ODS steel by using a 1.7 MeV tandem accelerator. The irradiation temperatures were 300°C and 500°C. The nominal displacement damage rate and total displacement damage were 1×10−3 dpa/s and up to 10 dpa at about 600-nm depth from the irradiated surface, respectively. Nano-indentation hardness was evaluated with a Berkovich indenter. After the ion-irradiation at 300°C up to 1 dpa, the normalized nano-indentation hardness (hardness after irradiation/hardness before irradiation) of the K3 ODS steel reached about 1.28 and the value showed no change up to 10 dpa. On the other hand, the ion-irradiation at 500°C up to 10 dpa showed no significant irradiation hardening. TEM observation revealed that dense and fine dislocation loops were formed in the ion-irradiated steels at 300°C, which were probably enough to explain the irradiation hardening.

    Keywords:

    ODS ferritic steel, irradiation hardening, microstructure, ion-irradiation, nano-indentation


    Paper ID: STP46570S

    Committee/Subcommittee: E10.07

    DOI: 10.1520/STP46570S


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