STP782: Nickel-Doped Ferritic (Martensitic) Steels for Fusion Reactor Irradiation Studies: Tempering Behavior and Unirradiated and Irradiated Tensile Properties

    Klueh, RL
    Metals and Ceramics Division, Oak Ridge National Laboratory, Oak Ridge, TN

    Vitek, JM
    Metals and Ceramics Division, Oak Ridge National Laboratory, Oak Ridge, TN

    Grossbeck, ML
    Metals and Ceramics Division, Oak Ridge National Laboratory, Oak Ridge, TN

    Pages: 17    Published: Jan 1982


    Abstract

    When an alloy containing nickel is irradiated in a mixed-spectrum reactor, helium is produced in the lattice by the transmutation of 58Ni by thermal neutrons. Nickel doping of two ferritic (martensitic) steels is being used to determine the effect of simultaneously produced helium and displacement damage (produced by the fast neutrons in the spectrum) on the mechanical properties of these steels, which are structural candidates for fusion reactor applications. Heats of 9 Cr-1 MoVNb and 12 Cr-1 MoVW with up to 2% Ni have been prepared. Tempering studies were conducted to determine the effect of nickel on the basic alloys and to identify the appropriate tempering temperature and time. Tensile specimens of the steels were irradiated in the High Flux Isotope Reactor to displacement damage levels of up to 9.3 dpa and helium concentrations of up to 82 at. ppm. Tensile studies at room temperature and 300°C on the 9 Cr-1 MoVNb steels indicated that the irradiation led to increased strength and decreased ductility compared to the steels in the unirradiated condition. It was concluded that the hardening resulted from the displacement damage and was not affected by the transmutation helium. The results were similar to tensile properties previously obtained for nickel-doped 12 Cr-1 MoVW steel irradiated under similar conditions.

    Keywords:

    radiation effects, ferritic (martensitic) steels, tempering effects, hardness, tensile properties, ductility, irradiation hardening, helium effects


    Paper ID: STP34371S

    Committee/Subcommittee: E10.07

    DOI: 10.1520/STP34371S


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