Chapter 25. Localised Damage in Continuous Fibre Reinforced Ceramic Matrix Composites
- John B. Wachtman Jr.
Published Online: 26 MAR 2008
Copyright © 1993 The American Ceramic Society
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
Powell, K. L., Yeomans, J. A. and Smith, P. A. (1993) Localised Damage in Continuous Fibre Reinforced Ceramic Matrix Composites, 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.ch25
- Published Online: 26 MAR 2008
- Published Print: 1 JAN 1993
Print ISBN: 9780470375273
Online ISBN: 9780470314234
- thermal expansion;
- confocal scanning laser microscopy (CSLM)
As a precursor to a study of erosive wear behaviour of ceramic matrix composites, fracture introduced by indentation and single particle impact has been studied in two glass-ceramic/silicon carbide fibre composite systems. The damage has been characterised and quantified using a combination of confocal scanning laser microscopy and scanning electron microscopy. Lateral cracks, which form approximately parallel to the surface, have been found to be the predominant damage event. In the calcium alumino-silicate (CAS)/Nicalon system, lateral cracks tend, to form in regions of the matrix which have a high local fibre volume fraction, whilst in the barium magnesium alumino silicate (BMAS)/Tyranno system they tend to avoid fibre-rich regions. These results are consistent with an analysis of residual thermal stresses in the two systems. In CAS/Nicalon the coefficient of thermal expansion of the matrix is greater than that of the fibre. This puts the matrix into axial tension at room temperature with the stress increasing with local fibre volume fraction. In BMAS/Tyranno the reverse is the case. Thus in both systems, the observed damage is a consequence of the residual stress as well as the stress due to the contact event.