Chapter 4. Microstructure and Mechanical Behavior of an Hibonite Interphase in Alumina-Based Composites

  1. John B. Wachtman Jr.
  1. Michael K. Cinibulk

Published Online: 26 MAR 2008

DOI: 10.1002/9780470314784.ch4

Proceedings of the 19th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures - B: Ceramic Engineering and Science Proceedings, Volume 16, Issue 5

Proceedings of the 19th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures - B: Ceramic Engineering and Science Proceedings, Volume 16, Issue 5

How to Cite

Cinibulk, M. K. (1995) Microstructure and Mechanical Behavior of an Hibonite Interphase in Alumina-Based Composites, in Proceedings of the 19th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures - B: Ceramic Engineering and Science Proceedings, Volume 16, Issue 5 (ed J. B. Wachtman), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470314784.ch4

Author Information

  1. UES, Inc., Dayton Ohio 45432-1894

Publication History

  1. Published Online: 26 MAR 2008
  2. Published Print: 1 JAN 1995

ISBN Information

Print ISBN: 9780470375389

Online ISBN: 9780470314784

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Keywords:

  • hibonite;
  • magnetoplumbite;
  • crystallographically;
  • anisotropy;
  • microstructure

Summary

A textured calcium hexaluminate (CaAl12O19, hibonite) interphase has been obtained with basal cleavage planes aligned in the plane of the interphase in alumina fiber-reinforced composites and in between alumina substrates as a bonding layer. Measurements of the critical strain-energy release rate of hibonite-bonded alumina substrates gave Gss=2.2 J/m2, while SEM observations indicated crack propagation through the interphase by cleavage. TEM observations of the interphase in fiber-reinforced composites showed crack deflection and propagation by cleavage within the interphase, suggesting that such an interphase is capable of protecting the fibers. However, strong radial compressive stresses, arising from thermal expansion mismatch in single-crystal alumina fiber-reinforced composites, and interfacial roughness upon debonding most likely dominate fiber pushout/pullout.