Chapter 53. Indentation Fracture of Silicon Nitride-Based Ceramic Matrix Composites (SN CMC's)

  1. John B. Wachtman Jr.
  1. A. G. Solomah1,
  2. A. Tucci2 and
  3. L. Esposito2

Published Online: 26 MAR 2008

DOI: 10.1002/9780470314234.ch53

Proceedings of the 17th Annual Conference on Composites and Advanced Ceramic Materials, Part 2 of 2: Ceramic Engineering and Science Proceedings, Volume 14, Issue 9/10

Proceedings of the 17th Annual Conference on Composites and Advanced Ceramic Materials, Part 2 of 2: Ceramic Engineering and Science Proceedings, Volume 14, Issue 9/10

How to Cite

Solomah, A. G., Tucci, A. and Esposito, L. (1993) Indentation Fracture of Silicon Nitride-Based Ceramic Matrix Composites (SN CMC's), in Proceedings of the 17th Annual Conference on Composites and Advanced Ceramic Materials, Part 2 of 2: Ceramic Engineering and Science Proceedings, Volume 14, Issue 9/10 (ed J. B. Wachtman), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470314234.ch53

Author Information

  1. 1

    SAC International Ceramics, 13–1445 Bonhill Road, Mississauga, Ontario L5T 1V3 Canada

  2. 2

    Centro Ceramico, 26 via Martelli, Bologna, 40138, Italy

Publication History

  1. Published Online: 26 MAR 2008
  2. Published Print: 1 JAN 1993

ISBN Information

Print ISBN: 9780470375273

Online ISBN: 9780470314234

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Keywords:

  • propagation;
  • diagonal;
  • microstructural;
  • indentation;
  • reliability

Summary

Vickers indentation technique has been successfully utilized to investigate the fracture behaviour of different silicon nitride-based ceramic matrix composites (SAC SN CMC's) at room temperature under ambient atmosphere having 50% relative humidity and under oil film coating simulating inert atmosphere. Effects of indentation load and humidity on crack length measurements and crack propagation under the two above mentioned atmospheres have been investigated. Significant post-indentation crack growth in silicon nitride-based ceramic matrix composites has been observed under humid atmospheric conditions which has been attributed to stress corrosion-assisted crack propagation (SCACP) mechanism. Effects of sintering additives which constitute the grain boundary phases on post-indentation crack growth (PICG) have shown that the lower the percentages of sintering additives, the more the materials are resistant to PICG. The relationship between crack length, c, (measured from the centre of the impression diagonal to the crack tip) and indentation load, P, was found to follow the formula: [equation] where the exponent q is a function of microstructural features of the material which dominate the shape of the crack propagation, i.e. crack deflection, bridging, branching, etc.