Chapter 20. Elevated-Temperature, ‘Ultra’-Fast Fracture Strength of Silicon Nitride Ceramics

  1. Don Bray
  1. Sung R. Choi1 and
  2. John P. Gyekenyesi2

Published Online: 26 MAR 2008

DOI: 10.1002/9780470294482.ch20

22nd Annual Conference on Composites, Advanced Ceramics, Materials, and Structures: A: Ceramic Engineering and Science Proceedings, Volume 19, Issue 3

22nd Annual Conference on Composites, Advanced Ceramics, Materials, and Structures: A: Ceramic Engineering and Science Proceedings, Volume 19, Issue 3

How to Cite

Choi, S. R. and Gyekenyesi, J. P. (1988) Elevated-Temperature, ‘Ultra’-Fast Fracture Strength of Silicon Nitride Ceramics, in 22nd Annual Conference on Composites, Advanced Ceramics, Materials, and Structures: A: Ceramic Engineering and Science Proceedings, Volume 19, Issue 3 (ed D. Bray), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470294482.ch20

Author Information

  1. 1

    Cleveland State University, Cleveland, OH 44115, USA

  2. 2

    NASA Lewis Research Center, Cleveland, OH 44135, USA

Publication History

  1. Published Online: 26 MAR 2008
  2. Published Print: 1 JAN 1988

ISBN Information

Print ISBN: 9780470375587

Online ISBN: 9780470294482

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Keywords:

  • nitride;
  • silicon;
  • ceramic;
  • environment;
  • alumina

Summary

The determination of ‘ultra’-fast fracture strengths of five silicon nitride ceramics at elevated temperatures has been made by using constant stress-rate (“dynamic fatigue”) testing in flexure with a series of ‘ultra’-fast test rates. Of the five test materials, four silicon nitrides had elevated-temperature strengths that approached their respective room-temperature strengths at an ‘ultra’-fast test rate of 3.3 × 104 MPa/s. This implies that slow crack growth (SCG) responsible for elevated-temperature failure can be eliminated or minimized by using an ‘ultra’-fast test rate. These ongoing experimental results have shed light on laying a theoretical and practical foundation on the concept and definition of elevated-temperature “inert” strength behavior of advanced ceramics.