Chapter 18. Creep and Creep Rupture of HIP'ed Si3N4
- John B. Wachtman Jr
Published Online: 26 MAR 2008
Copyright © 1991 The American Ceramic Society, Inc.
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
- Published Online: 26 MAR 2008
- Published Print: 1 JAN 1991
Print ISBN: 9780470375105
Online ISBN: 9780470313848
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.