Chapter 9. Crack Growth in Sapphire

  1. Hua-Tay Lin and
  2. Mrityunjay Singh
  1. Sheldon M. Wiederhom and
  2. Ralph F. Krause Jr

Published Online: 26 MAR 2008

DOI: 10.1002/9780470294741.ch9

26th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures: A: Ceramic Engineering and Science Proceedings, Volume 23, Issue 3

26th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures: A: Ceramic Engineering and Science Proceedings, Volume 23, Issue 3

How to Cite

Wiederhom, S. M. and Krause, R. F. (2002) Crack Growth in Sapphire, in 26th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures: A: Ceramic Engineering and Science Proceedings, Volume 23, Issue 3 (eds H.-T. Lin and M. Singh), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470294741.ch9

Author Information

  1. National Institute of Standards and Technology Gaithersburg, MD 20899

Publication History

  1. Published Online: 26 MAR 2008
  2. Published Print: 1 JAN 2002

ISBN Information

Print ISBN: 9780470375785

Online ISBN: 9780470294741

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Keywords:

  • stress-intensity factor;
  • radiation;
  • velocity;
  • stress sensitivity;
  • propagation

Summary

Crack growth was studied in sapphire on both the m-plane and the r-plane (rhombohedral twin plane). The crack growth rate on the m-plane was expressed in terms of a power law function of stress-intensity factor and an Arrhenius function of temperature. Crack growth on r-plane double-torsion specimens was irregular. Spurts of growth on the r-plane were mixed with propagation on rough surfaces. Control of crack growth was not possible. Our studies suggest that r-plane fracture requires a lower K1 than that on the m-plane. We suggest that propagation on the r-plane may be associated with twinning at the crack tip during or prior to crack growth.