Chapter 61. Slow Crack Growth in Alumina with R-Curve at Elevated Temperatures

  1. John B. Wachtman Jr
  1. James E. Webb,
  2. Karl Jakus and
  3. John E. Ritter

Published Online: 26 MAR 2008

DOI: 10.1002/9780470314715.ch61

Proceedings of the 19th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures - A: Ceramic Engineering and Science Proceedings, Volume 16, Issue 4

Proceedings of the 19th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures - A: Ceramic Engineering and Science Proceedings, Volume 16, Issue 4

How to Cite

Webb, J. E., Jakus, K. and Ritter, J. E. (1995) Slow Crack Growth in Alumina with R-Curve at Elevated Temperatures, in Proceedings of the 19th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures - A: Ceramic Engineering and Science Proceedings, Volume 16, Issue 4 (ed J. B. Wachtman), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470314715.ch61

Author Information

  1. Department of Mechanical Engineering, University of Massachusetts Amherst, MA 01003

Publication History

  1. Published Online: 26 MAR 2008
  2. Published Print: 1 JAN 1995

ISBN Information

Print ISBN: 9780470375372

Online ISBN: 9780470314715

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Keywords:

  • R-curve;
  • chevron;
  • intrinsic;
  • predicted;
  • friction

Summary

The effect of temperature and slow crack growth on the R-curve in a 99.5% purity coarse grained alumina was studied using chevron notched short bar specimens. Constant loading rate tests were used to measure toughness as a function of crack length and static load tests were used to measure slow crack growth as a function of time. It was found that the intrinsic toughness decreased with temperature while the bridging contribution to the R-curve remained relatively independent of temperature. The constant load tests at 1000°C showed slow crack growth with an n-value of 64 indicative of a Region III type of behavior. Using the slow crack growth parameters derived from the constant load tests, the effect of loading rate was predicted for the constant loading rate tests. The predicted decrease in the applied stress intensity for five orders of magnitude decrease in loading rate was slightly larger than the range of scatter in the data. The predictions suggested that slow crack growth could influence R-curve measurements when slow crack growth is aggressive and the tests are performed at too slow of a loading rate.