Intergranular segregation in the pressure vessel steel of a commercial nuclear reactor studied by atom probe tomography

Takeshi Toyama, Yasuyoshi Nagai, Abderrahim Al Mazouzi, Masahiko Hatakeyama, Masayuki Hasegawa, Tadakatsu Ohkubo, Eric van Walle, Robert Gérard

    Research outputpeer-review

    6 Scopus citations

    Abstract

    Solute/impurity segregation and precipitation at grain boundaries (GBs) in a nuclear reactor pressure vessel (RPV) steel were investigated using laser-assisted atom probe tomography (APT): RPV surveillance test specimens irradiated in a commercial nuclear reactor to neutron doses of 0.83 × 1019 n•cm2 (low-dose) and 5.1 × 1019 n•cm2 (high-dose), corresponding to in-service exposure of ∼5 and ∼30 years, respectively. The segregation of C, P and Mo was found on GBs after the low-dose irradiation. The segregation of Si and Mn as well as C, P and Mo was observed after the high-dose irradiation. The monolayer coverage of P is estimated to be less than a suggested level for intergranular embrittlement. The segregation of C, P and Mo was also observed along parallel array of dislocation lines in small-angle grain boundaries. However, no segregation of Si and Mn was detected there. Copper-nano precipitates (CNPs) were observed on the GBs, along the dislocation lines and in the matrix. The sizes and the solute-impurity enrichment in these CNPs are compared.

    Original languageEnglish
    Pages (from-to)2119-2124
    Number of pages6
    JournalMaterials Transactions
    Volume54
    Issue number11
    DOIs
    StatePublished - 2013

    ASJC Scopus subject areas

    • Materials Science(all)
    • Condensed Matter Physics
    • Mechanics of Materials
    • Mechanical Engineering

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