Microstructure and Mechanical Properties of Hot-Pressed Silicon Carbide-Aluminum Nitride Compositions

Authors

  • Youren Xu,

    1. Materials Research Laboratory and Department of Materials Science and Engineering, University of Illinois, Urbana, Illinois 61801
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    • *

      Member, American Ceramic Society.

  • Avigdor Zangvil,

    1. Materials Research Laboratory and Department of Materials Science and Engineering, University of Illinois, Urbana, Illinois 61801
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    • *

      Member, American Ceramic Society.

  • Martine Landon,

    1. Department Materiaux, Ecole Nationale Superieure des Mines de Saint-Etienne 42023 Saint-Etienne Cedex 2, France
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  • François Thevenot

    1. Department Materiaux, Ecole Nationale Superieure des Mines de Saint-Etienne 42023 Saint-Etienne Cedex 2, France
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      Member, American Ceramic Society.


  • D. J. Green—contributing editor

  • Presented in part at the 93rd Annual Meeting of the American Ceramic Society, Cincinnati, OH, April 29, 1991 (Paper No. 2-SVIP–91).

  • Supported by the U.S. Department of Energy, Division of Materials Sciences, under Contract No. DEFG02–91ER–45439.

Abstract

A flexural strength of up to 1 GPa was achieved in SiC-AIN materials and is attributed to a dense, equiaxial grain structure of the 2H(δ) SiC-AIN solid solution, with a relatively uniform grain size of ∼ 1 μm. The strength was found to decrease with increasing grain size. While the β→α phase transformation and the formation of various metastable polytypes make microstructural control difficult in SiC materials, excellent control is facilitated in SiC-AIN materials as a result of the stable 2H solid solution. Several mechanisms of grain refinement during the β→ 2H transition were observed, most notably the direct formation of several 2H grains from a single β grain. In addition, grain growth is limited by the diffusion-controlled nature of the transition. These mechanisms could be utilized to achieve even higher strength values, with potentially higher reliability of the materials in structural applications.

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