STP725: Fracture Resistance of HT-9 After Irradiation at Elevated Temperature

    Smidt, FA
    Supervisory metallurgist and research metallurgists, Naval Research LaboratoryTracor, Inc., WashingtonRockville, D.C.Md.

    Hawthorne, JR
    Supervisory metallurgist and research metallurgists, Naval Research LaboratoryTracor, Inc., WashingtonRockville, D.C.Md.

    Provenzano, V
    Supervisory metallurgist and research metallurgists, Naval Research LaboratoryTracor, Inc., WashingtonRockville, D.C.Md.

    Pages: 16    Published: Jan 1981


    Abstract

    HT-9, a 12 percent chromium martensitic stainless steel of interest for use in ducts for fast reactors and as a first-wall material in magnetic fusion reactors, was irradiated in the experimental breeder reactor II to obtain the first evaluation of fracture toughness changes produced by high-temperature/high-fluence irradiation in this class of alloy.

    Charpy V-notch, precracked Charpy, and tension specimens were used to evaluate the tensile and fracture behavior of this steel in the as-received condition, after 5000 h of aging at 427 and 538°C and after irradiation to a fluence of 1.1 × 1022 neutron/cm2 (E > 0.1 MeV) at 419°C in flowing sodium. The results show some tendency toward temper embrittlement at 538°C and a 108 deg C shift in the ductile-to-brittle transition after irradiation at 419°C. Charpy-V energies on the upper shelf are also depressed by the irradiation but maintain adequate levels for the applications intended. Possible mechanisms for the observed response are discussed.

    Keywords:

    breeder reactor materials, magnetic fusion reactor materials, martensitic stainless steel, irradiation embrittlement


    Paper ID: STP28219S

    Committee/Subcommittee: E10.07

    DOI: 10.1520/STP28219S


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