STP1245

    Oxidation of Intermetallic Precipitates in Zircaloy-4: Impact of Irradiation

    Published: Jan 1994


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    Abstract

    Intermetallic precipitates are known to play a critical role in the oxidation process of Zircaloys. Since under irradiation they undergo structural changes, a specific study was conducted to analyze whether these transformations modify the oxidation behavior of the Zircaloy-4. Oxidation kinetics in autoclave were measured on reference, ion irradiated, and neutron irradiated materials. In the case of ion-irradiated samples, the oxidation kinetics are changed, while in the case of neutron-irradiated cladding, no significant change is observed after 60 days of oxidation. The behavior of reference and irradiated precipitates during the growth of these oxide layers was analyzed using analytical scanning transmission electron microscopy. Close to the metal-oxide interface, precipitates are incorporated unoxidized in the oxide layer. Then, when oxidized, at a few hundreds of nanometers from this interface, they undergo two major evolutions: their structure becomes either nanocrystalline or occasionally amorphous and an iron redistribution and depletion is observed. In the case of precipitates previously made amorphous by irradiation, a similar behavior is observed. The role of precipitates on the oxidation of the Zircaloy-4 is discussed in terms of interaction of the precipitates with the zirconia layer (stability of the dense oxide layer) and oxidation kinetics.

    Keywords:

    zirconium, precipitates, oxidation, oxide layer, oxidation kinetics, zirconia, irradiation, amorphization, analytical scanning transmission electron microscopy, zirconium alloys, nuclear materials, nuclear applications, radiation effects


    Author Information:

    Pêcheur, D
    Research engineers and head of Laboratory, CEA-Grenoble, DTP/SECC, 85X, Grenoble,

    Lefebvre, F
    Research engineers and head of Laboratory, CEA-Grenoble, DTP/SECC, 85X, Grenoble,

    Motta, AT
    Assistant professor, Pennsylvania State University, University Park, PA

    Lemaignan, C
    Research engineers and head of Laboratory, CEA-Grenoble, DTP/SECC, 85X, Grenoble,

    Charquet, D
    Research engineer, Centre de Recherches d'Ugine, Ugine,


    Paper ID: STP15215S

    Committee/Subcommittee: B10.02

    DOI: 10.1520/STP15215S


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