STP1245

    Microstructure of Oxide Layers Formed During Autoclave Testing of Zirconium Alloys

    Published: Jan 1994


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    Abstract

    The microstructure of oxide layers formed in steam in a 400°C, 10.3-MPa autoclave on different zirconium alloys was studied by transmission electron microscopy. Pre-and post-transition oxide layers on Zircaloy-4 with different heat treatments, and post-transition oxide layers on Zr-0.5Sn-0.53Nb were compared. Special attention was paid to the oxide-metal interface. In Zircaloy-4 with short annealing times and high post-transition corrosion rates, the interface had a disordered structure, and pores were found in the oxide very close to the interface. In Zircaloy-4 with low uniform corrosion rates, the interface consisted of highly ordered, columnar grains. The interface in Zr-0.5Sn-0.53Nb had a different appearance, with an intermediate phase of equiaxed grains between the columnar oxide and the metal. The hydrogen absorption of the zirconium alloys during oxidation was measured by the melt extraction technique on samples oxidized for 63, 147, and 343 days. The Zr-0.5Sn0.53Nb alloy had considerably lower hydrogen absorption than Zircaloy-4.

    Keywords:

    zirconium alloys, niobium, uniform corrosion, corrosion resistance, autoclave testing, oxide growth, oxide-metal interface, transmission electron microscopy, hydrogen absorption, zirconium, nuclear materials, nuclear applications, radiation effects


    Author Information:

    Wadman, B
    Research students and associate professor, Chalmers University of Technology, Göteborg,

    Lai, Z
    Research students and associate professor, Chalmers University of Technology, Göteborg,

    Andrén, H-O
    Research students and associate professor, Chalmers University of Technology, Göteborg,

    Nyström, A-L
    Research engineer, AB Sandvik Steel, R&D Centre, Physical Metallurgy, Sandviken,

    Rudling, P
    Specialist, ABB Atom AB, Västerås,

    Pettersson, H
    Nuclear fuel engineer, Vattenfall Fuel, Nuclear Fuel Technology, Vällingby,


    Paper ID: STP15210S

    Committee/Subcommittee: B10.02

    DOI: 10.1520/STP15210S


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