Chapter 10. Fracture Toughness (KIc & γwof) of a HIPed Si3N4 at Elevated Temperatures
- John B. Wachtman Jr.
Published Online: 28 MAR 2008
Copyright © 1993 The American Ceramic Society
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
- Published Online: 28 MAR 2008
- Published Print: 1 JAN 1993
Print ISBN: 9780470375266
Online ISBN: 9780470314180
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.