Chapter 70. Ultrasonic Evaluation of Microcrack Thermal Shock Damage in Ceramics

  1. John B. Wachtman Jr.
  1. S. I. Rokhlin,
  2. Y. C. Chu and
  3. M. Hefetz

Published Online: 28 MAR 2008

DOI: 10.1002/9780470314180.ch70

Proceedings of the 17th Annual Conference on Composites and Advanced Ceramic Materials, Part 1 of 2: Ceramic Engineering and Science Proceedings, Volume 14, Issue 7/8

Proceedings of the 17th Annual Conference on Composites and Advanced Ceramic Materials, Part 1 of 2: Ceramic Engineering and Science Proceedings, Volume 14, Issue 7/8

How to Cite

Rokhlin, S. I., Chu, Y. C. and Hefetz, M. (1993) Ultrasonic Evaluation of Microcrack Thermal Shock Damage in Ceramics, in Proceedings of the 17th Annual Conference on Composites and Advanced Ceramic Materials, Part 1 of 2: Ceramic Engineering and Science Proceedings, Volume 14, Issue 7/8 (ed J. B. Wachtman), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470314180.ch70

Author Information

  1. The Ohio State University Department of Welding Engineering Columbus, Ohio 43210

Publication History

  1. Published Online: 28 MAR 2008
  2. Published Print: 1 JAN 1993

ISBN Information

Print ISBN: 9780470375266

Online ISBN: 9780470314180

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Keywords:

  • aluminum oxide;
  • degradation;
  • applicability;
  • ceramics;
  • mechanical

Summary

In this paper we present an experimental study of the effect of microcrack damage in ceramics on elastic properties and apply a microdamage model for data analysis. Ceramic samples of aluminum oxide and reaction bonded silicon nitride (RBSN) are used in the experiments. Thermal shock treatment from different temperatures up to 1000 °C is applied to produce the microcracks. Both surface and bulk ultrasonic wave methods are used to correlate the measurements to strength degradation and to determine the change in elastic anisotropy induced by micro-crack damage. For the theoretical investigation, a damage model, which relates microstructural damage to mechanical properties, is used. The change in elastic properties due to microcrack damage calculated from the theoretical model is compared with the experimental results for determination of the applicability of damage theory. It is shown that two independent experimental methods (bulk wave and surface wave) give the same results for shear moduli of damaged ceramics. The experimental results agree reasonably well with the moduli predicted from the cracked solid model.