High temperature plastic flow and grain boundary chemistry in oxide ceramics

H. Yoshida, A. Kuwabara, T. Yamamoto, Y. Ikuhara, T. Sakuma

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    11 Citations (Scopus)

    Abstract

    High temperature plastic flow or grain boundary failure in oxide ceramics such as Al2O3 and tetragonal ZrO2 polycrystal (TZP) is sensitive to small levels of doping by various cations. For example, high temperature creep deformation in fine-grained, polycrystalline Al 2O3 is highly suppressed by 0.1 mol% lanthanoid oxide or ZrO2-doping. An elongation to failure in superplastic TZP is improved by 0.2-3 mol% GeO2-doping. A high-resolution transmission electron microscopy (HRTEM) observation and an energy-dispersive X-ray spectroscopy (EDS) analysis revealed that the dopant cations tend to segregate along the grain boundaries in Al2O3 and TZP. The dopant effect is attributed to change in the grain boundary diffusivity due to the grain boundary segregation of the dopant cations. A molecular orbital calculation suggests that ionicity is one of the most important parameters to determine the high temperature flow stress, and probably, the grain boundary diffusivity in the oxide ceramics.

    Original languageEnglish
    Pages (from-to)3129-3135
    Number of pages7
    JournalJournal of Materials Science
    Volume40
    Issue number12
    DOIs
    Publication statusPublished - 2005 Jun

    ASJC Scopus subject areas

    • Materials Science(all)
    • Mechanics of Materials
    • Mechanical Engineering

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