Chapter 33. High Temperature Mechanical Properties of SiAlON Ceramics: Microstructural Effects
- William Smothers
Published Online: 26 MAR 2008
Copyright © 1987 The American Ceramic Society, Inc.
11th Annual Conference on Composites and Advanced Ceramic Materials: Ceramic Engineering and Science Proceedings, Volume 8, Issue 7/8
How to Cite
Chen, C.-F. and Tien, T.-Y. (1987) High Temperature Mechanical Properties of SiAlON Ceramics: Microstructural Effects, in 11th Annual Conference on Composites and Advanced Ceramic Materials: Ceramic Engineering and Science Proceedings, Volume 8, Issue 7/8 (ed W. Smothers), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470320402.ch33
- Published Online: 26 MAR 2008
- Published Print: 1 JAN 1987
Print ISBN: 9780470374733
Online ISBN: 9780470320402
Tensile creep of both as-hot-pressed and annealed SiAlON-YAG ceramics has been identified as creep damage (cavitation and cavity growth) the mechanism dominating the creep life. The hot-pressed sample has β-SiAlON grain as the only crystalline phase surrounded by a vitreous matrix. When this material sustains creep, cavities nucleate within the multigrain junctions and the majority of cavities are followed by viscous flow growth. However, the annealed sample has β-SiAlON grain surrounded by crystalline YAG. When this material sustains creep, cavities nucleate at the interphase of SiAlON and YAG phases and the majority of cavities are followed by diffusive crack growth. Creep curves and TEM post-crept investigation shows that crystallizing the grain boundary vitreous phase can increase the creep life by reducing cavitation rate and cavity growth rate. Also, increasing the hot-pressing time can affect the creep behaviors by reducing the number of multigrain junctions, thus, decrease cavitation rate.