Positron annihilation in neutron irradiated iron-based materials

Marlies Lambrecht, Abderrahim Al Mazouzi, Lorenzo Malerba

    Research outputpeer-review


    The hardening and embrittlement of reactor pressure vessel steels is of great concern in the actual nuclear power plant life assessment. This embrittlement is caused by irradiation-induced damage. But the reason for the embrittlement of the material is not yet totally known. The real nature of the irradiation damage should thus be examined as well as its evolution in time. Positron annihilation spectroscopy has been shown to be a powerful method for analyzing some of these defects. In fact, both vacancy type clusters and precipitates can be visualized by positrons. To be able to compare the results obtained by the positron studies, with those of other techniques (such as transmission electron microscopy, atom probe tomography and small angle neutron scattering), quantitative estimations of the size and density of the annihilation sites are needed. Using the approach proposed by Vehanen et al., an attempt is made to calculate the needed quantities in Fe and Fe-Cu binary alloys that were neutron irradiated to different doses. The results obtained are discussed highlighting the difficulties in defining the annihilation centres even in these simple model alloys, in spite of using both lifetime and Doppler broadening measurements in the same samples.
    Original languageEnglish
    Pages (from-to)012009-012009
    JournalJournal of Physics: Conference Series
    Issue number1
    StatePublished - Jan 2011
    EventInternational Workshop on Positron Studies of Defects (PSD-08) - Charles University, Prague
    Duration: 1 Sep 20085 Sep 2008

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