Transmission electron microscope observation of creep-deformed Al2O3, SiC and Si3N4 ceramics

T. Yano, Toshimitsu Yokobori

    Research output: Contribution to journalConference articlepeer-review

    Abstract

    Microstructural observation using transmission electron microscope were conducted on creep-deformed SiC, Al2O3 and Si3N4 ceramics in order to analyze microscopic deformation mechanism in these ceramics directly. Thin foils were prepared from the tensile surface of the four-point bending bars after creep test at various conditions. In SiC ceramics crept at 1250°C, very sharp microcracks propagated relatively straight and transgranularly. Microcracks also branched and some of them extended along grain boundary. In SiC crept at 1480°C, grain boundary cavities and dislocations were also observed. In Si3N4 crept at around 1200°C, cavities along grain boundary were frequently observed. Dislocations were sometimes observed. No transgranular cracks were happened. In Al2O3 ceramics crept at 1000°C, sharp microcracks ran through both grain boundary and inside grains with small number of very tiny grain boundary cavities. Grain boundary glassy phase was partly crystallized. Based on the observed microstructure, creep mechanisms of these ceramics were discussed in relation with creep ductility.

    Original languageEnglish
    Pages (from-to)833-840
    Number of pages8
    JournalKey Engineering Materials
    Volume171-174
    Publication statusPublished - 2000 Jan 1
    EventProceedings of the 1999 8th International Conference on Creep and Fracture of Engineering Materials and Structures - Tsukuba, Jpn
    Duration: 1999 Nov 11999 Nov 5

    ASJC Scopus subject areas

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

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