Structure of screw dislocations in a (0 0 0 1)/[0 0 0 1] low-angle twist grain boundary of alumina (α-Al 2O 3)

E. Tochigi, Y. Kezuka, N. Shibata, A. Nakamura, Y. Ikuhara

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    16 Citations (Scopus)

    Abstract

    An alumina (α-Al 2O 3) bicrystal with a (0 0 0 1)/[0 0 0 1] low-angle twist grain boundary was fabricated by bonding two (0 0 0 1) substrates at 1500 °C in air. Dislocation structures in the resultant grain boundary were extensively observed in plan view and cross-sectional direction by transmission electron microscopy (TEM). The grain boundary consisted of a hexagonal dislocation network of 1/3〈12̄10〉 basal screw dislocations and wavy belt structures. The atomic core structure of the screw dislocations was analyzed in end-on view by high-resolution TEM. It was evident that the 1/3〈12̄10〉 basal screw dislocation does not dissociate into partial dislocations, which is in contrast to the 1/3〈12̄10〉 basal edge dislocation that dissociates into 1/3〈11̄00〉 and 1/3〈01̄10〉 partial dislocations. Also, TEM observation revealed that the wavy belt structures correspond to planar voids. From the morphology of the planar voids, it is considered that they accommodate a slight tilt component of the boundary.

    Original languageEnglish
    Pages (from-to)1293-1299
    Number of pages7
    JournalActa Materialia
    Volume60
    Issue number3
    DOIs
    Publication statusPublished - 2012 Feb

    Keywords

    • Alumina (α-Al O )
    • Sapphire
    • Screw dislocation
    • Transmission electron microscopy (TEM)
    • Twist grain boundary

    ASJC Scopus subject areas

    • Electronic, Optical and Magnetic Materials
    • Ceramics and Composites
    • Polymers and Plastics
    • Metals and Alloys

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