Chapter 18. Creep and Creep Rupture of HIP'ed Si3N4

  1. John B. Wachtman Jr
  1. David C. Cranmer1,
  2. Bernard J. Hockey1,
  3. Sheldon M. Wiederhorn1 and
  4. Russell Yecklev2

Published Online: 26 MAR 2008

DOI: 10.1002/9780470313848.ch18

Proceedings of the 15th Annual Conference on Composites and Advanced Ceramic Materials, Part 2 of 2: Ceramic Engineering and Science Proceedings, Volume 12, Issue 9/10

Proceedings of the 15th Annual Conference on Composites and Advanced Ceramic Materials, Part 2 of 2: Ceramic Engineering and Science Proceedings, Volume 12, Issue 9/10

How to Cite

Cranmer, D. C., Hockey, B. J., Wiederhorn, S. M. and Yecklev, R. (1991) Creep and Creep Rupture of HIP'ed Si3N4, in Proceedings of the 15th Annual Conference on Composites and Advanced Ceramic Materials, Part 2 of 2: Ceramic Engineering and Science Proceedings, Volume 12, Issue 9/10 (ed J. B. Wachtman), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470313848.ch18

Author Information

  1. 1

    Ceramics Division National Institute of Standards and Technology Gaithersburg, MD 20899

  2. 2

    Norton/TRW Ceramics Northboro, MA 01532

Publication History

  1. Published Online: 26 MAR 2008
  2. Published Print: 1 JAN 1991

ISBN Information

Print ISBN: 9780470375105

Online ISBN: 9780470313848

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Keywords:

  • temperature;
  • deformation;
  • ceramics;
  • microstructure;
  • yttrium

Summary

The creep and creep rupture behavior of a hot isostatically pressed Si3N4 containing 4 wt% Y2O3 was examined as a function of temperature (1300°–1430ď) and applied stress (75-150 MPα). Creep rates varied from ≈10-10 to ≈10-9 S-1. Transient creep dominated the deformation behavior for all conditions examined. The creep strain was found to fit a power law function of applied stress. Initially, the material exhibited an apparent activation energy for creep of ≈600 kJ/mol. Long-term exposure to elevated temperature resulted in an increase in the apparent activation energy to ≈1250 kJ/mol. The time-to-rupture was found to fit a power law function of the minimum strain rate, independent of applied stress or temperature. The strain rate exponent was-1.12. Rupture appears to occur via the formation and link-up of lenticular-shaped cavities along grain boundaries. Lifetime prediction curves were obtained to establish the maximum service time at stress for a given temperature.