Chapter 44. Design of Fiber\Coating Systems for High Strength in Ceramic Matrix Composites

  1. Mrityunjay Singh and
  2. Todd Jessen
  1. Zhenhai Xia and
  2. William A. Curtin

Published Online: 26 MAR 2008

DOI: 10.1002/9780470294680.ch44

25th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures: A: Ceramic Engineering and Science Proceedings, Volume 22, Issue 3

25th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures: A: Ceramic Engineering and Science Proceedings, Volume 22, Issue 3

How to Cite

Xia, Z. and Curtin, W. A. (2001) Design of Fiber\Coating Systems for High Strength in Ceramic Matrix Composites, in 25th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures: A: Ceramic Engineering and Science Proceedings, Volume 22, Issue 3 (eds M. Singh and T. Jessen), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470294680.ch44

Author Information

  1. Brown University, Providence, RI 02912, USA

Publication History

  1. Published Online: 26 MAR 2008
  2. Published Print: 1 JAN 2001

ISBN Information

Print ISBN: 9780470375730

Online ISBN: 9780470294680

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Keywords:

  • ceramic;
  • composite;
  • temperature;
  • phenomena;
  • axisymmetric

Summary

A finite element model is used to study the stresses arising in ceramic matrix composites with different coatings and sliding interfaces. Stress concentrations in the fibers are found near matrix cracks, and their magnitudes depend on the location of the debonded interface and the sliding interfacial shear stress. When debonding occurs away from the fiber surface, fiber flaws are constrained from opening by the coating and fibers are effectively stronger. The probability of flaw failure under the computed stress fields is calculated and used in the Global Load Sharing model to predict composite strength. Results show that composite strength can be optimized by using fibers with a low Weibull modulus m and by designing interfaces with high interfacial shear stress l, but with debonding away from the fiber\coating interface. These guidelines are consistent with data on “low” strengths in SiC\Glass composites (high m, high Z, fiber\coating debonding) and “high” strengths of SiC\SiC with multilayer coatings (low m, high Z, debonding in coating).