STP1447

    Peculiarities of Structural and Behavioral Changes of Some Zirconium Alloys at Damage Doses of Up to 50 dpa

    Published: Jan 2004


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    Abstract

    The irradiation-induced damage of zirconium alloys subjected to neutron irradiation up to dose levels of ∼50 dpa was investigated. Specimens of unalloyed zirconium, Zr-1%Nb, Zr-2.5%Nb and Zr-1%Nb-1.3%Sn-0.4%Fe were irradiated in the BOR-60 reactor over the temperature range 320–420°C. The dose dependence of the irradiation growth strain increased sharply in zirconium and Zr-Nb irradiated at ∼350°C at doses above ∼10 dpa. In the case of Zr-1%Nb-1.3%Sn-0.4%Fe, it increased at doses of ∼37 dpa. Upon increasing the irradiation temperature to 420°C, a sharp accelerated irradiation growth of the Zr-1%Nb alloy began shifting up to about 30 dpa. For the Zr- 1%Nb-1.3%Sn-0.4%Fe, no change of the irradiation growth rate was observed up to a dose of 55 dpa. The onset of increased irradiation growth in alloys correlates with the occurrence of c-component dislocation loops which coincides with a loss of coherence of finely-dispersed precipitates. Post-irradiation annealing experiments demonstrated that a delay in loop formation leads to displacement of the “break-away” beginning in the dose dependence of the irradiation growth in the direction of high doses. The <a+c>-type dislocation loops were also formed in Zr-1%Nb alloy at high doses, but their influence on the change of macroscopic properties was not observed.

    The high dose irradiation resulted in a change of composition: the hcp matrix solid solution was depleted in niobium; a gradient of concentrations was noted along the radius of (ZrNb)2Fe particles occurring in the Zr-1 %Nb-1.3%Sn-0.4%Fe. The microstructure of Zr-2.5%Nb quenched from β-phase and then tempered was investigated after irradiation up to high doses at the low temperature of $#x223C;80°C. Irradiation-induced precipitates of β- Nb were observed, with concentration increasing with increasing irradiation damage rate.

    Keywords:

    zirconium, irradiation growth, microstructure, damage dose


    Author Information:

    Kobylyansky, GP
    Leading Research Scientist, Head of Department, Head of Laboratory, Senior Research Scientist, Junior Research Scientist, State Scientific Center of Russian Federation Research Institute of Atomic Reactors, Dimitrovgrad, Ulyanovsk region

    Novosyolov, AE
    Leading Research Scientist, Head of Department, Head of Laboratory, Senior Research Scientist, Junior Research Scientist, State Scientific Center of Russian Federation Research Institute of Atomic Reactors, Dimitrovgrad, Ulyanovsk region

    Ostrovsky, ZE
    Leading Research Scientist, Head of Department, Head of Laboratory, Senior Research Scientist, Junior Research Scientist, State Scientific Center of Russian Federation Research Institute of Atomic Reactors, Dimitrovgrad, Ulyanovsk region

    Shamardin, VK
    Leading Research Scientist, Head of Department, Head of Laboratory, Senior Research Scientist, Junior Research Scientist, State Scientific Center of Russian Federation Research Institute of Atomic Reactors, Dimitrovgrad, Ulyanovsk region

    Obuhov, AV
    Leading Research Scientist, Head of Department, Head of Laboratory, Senior Research Scientist, Junior Research Scientist, State Scientific Center of Russian Federation Research Institute of Atomic Reactors, Dimitrovgrad, Ulyanovsk region

    Shishov, VN
    Leading Research Scientist, Senior Research Scientist, Head of Laboratory, State Scientific Center of Russian Federation A.A. Bochvar All-Russian Research Institute of Inorganic Materials, Moscow,

    Peregud, MM
    Leading Research Scientist, Senior Research Scientist, Head of Laboratory, State Scientific Center of Russian Federation A.A. Bochvar All-Russian Research Institute of Inorganic Materials, Moscow,

    Nikulina, AV
    Leading Research Scientist, Senior Research Scientist, Head of Laboratory, State Scientific Center of Russian Federation A.A. Bochvar All-Russian Research Institute of Inorganic Materials, Moscow,


    Paper ID: STP11270S

    Committee/Subcommittee: E10.08

    DOI: 10.1520/STP11270S


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