Effects of microstructure on superplastic behavior and deformation mechanisms in β-silicon nitride ceramics

Guo Dong Zhan, Mamoru Mitomo, Yuichi Ikuhara, Taketo Sakuma

    Research output: Contribution to journalArticlepeer-review

    12 Citations (Scopus)

    Abstract

    The influence of grain shape and size on superplastic behavior and deformation mechanisms was investigated in annealed β-silicon nitride materials and compared with the results for hot-pressed material. The microstructure of the annealed materials consisted of fine equiaxed β-grains together with some elongated ones. Similar to the deformation behavior in the hot-pressed material, strain hardening did not occur in these annealed materials. Moreover, in contrast to the deformation behavior under tension, grain alignment under compression resulting from the development of a mild texture did not give rise to strain hardening. An annealed material with small elongated grains had a flow-stress dependency of n = 1, whereas other annealed materials with large elongated grains exhibited a flow-stress dependency of n = 1.6. In terms of texture development and the effect of grain shape on the creep rate when diffusion was the rate-controlling mechanism, a single curve with a stress exponent of approx. 1 and a grain-size exponent of 3 were obtained for all materials. This suggests that the deformation mechanism in these annealed materials was the same as that of fine equiaxed β-silicon nitride.

    Original languageEnglish
    Pages (from-to)3179-3184
    Number of pages6
    JournalJournal of the American Ceramic Society
    Volume83
    Issue number12
    DOIs
    Publication statusPublished - 2000 Jan 1

    ASJC Scopus subject areas

    • Ceramics and Composites
    • Materials Chemistry

    Fingerprint Dive into the research topics of 'Effects of microstructure on superplastic behavior and deformation mechanisms in β-silicon nitride ceramics'. Together they form a unique fingerprint.

    Cite this