Chapter 10. Fracture Toughness (KIc & γwof) of a HIPed Si3N4 at Elevated Temperatures

  1. John B. Wachtman Jr.
  1. A. A. Wereszczak1,
  2. M. K. Ferber1,
  3. R. R. Sanders1,
  4. M. G. Jenkins2 and
  5. P. Khandelwal3

Published Online: 28 MAR 2008

DOI: 10.1002/9780470314180.ch10

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

Wereszczak, A. A., Ferber, M. K., Sanders, R. R., Jenkins, M. G. and Khandelwal, P. (2008) Fracture Toughness (KIc & γwof) of a HIPed Si3N4 at Elevated Temperatures, 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.ch10

Author Information

  1. 1

    Oak Ridge National Laboratory, Oak Ridge, TN 37831-6064

  2. 2

    Department of Mechanical Engineering University of Washington Seattle, WA 98195

  3. 3

    Allison Gas Turbine Division, General Motors Corp. Indianapolis, IN 46206-0420

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:

  • temperatures;
  • geometric;
  • propagation;
  • microscopy;
  • intergranular

Summary

Chevron-notched bend bars of a hot isostatically pressed (HIPed) silicon nitride (PY6) were tested in three-point flexure in air at 25, 1000, 1200, 1300, and 1400°C. Stable crack growth was consistently produced at all the test temperatures. Average fracture toughness, KIc, and work of fracture, γwof, decreased from 6.4 Mpa·✓m and 52 J/m2, respectively, at 25°C to 4.5 Mpa·✓m and 44 J/m2 at 1200°C; a 29% and 15% decrease in KIc and γwof. Tests conducted at 1300°C and 1400°C activated high temperature deformation mechanisms, which effectively caused greater specimen ductility and apparent greater fracture resistances. At 1400°C, KIc and γwof were 6.5 Mpa·✓m and 159 J/m2, respectively.