Toughening of Ceramic Composite Designed by Silica-Based Transformation Weakening Interphases
| Periodical | Key Engineering Materials (Volume 287) |
|---|---|
| Main Theme | Advanced Si-Based Ceramics and Composites |
| Edited by | Hai-Doo Kim, Hua-Tay Lin and Michael J. Hoffmann |
| Pages | 358-366 |
| DOI | 10.4028/www.scientific.net/KEM.287.358 |
| Citation | Sang Jin Lee et al., 2005, Key Engineering Materials, 287, 358 |
| Online since | June, 2005 |
| Authors | Sang Jin Lee, C.H. Lee, Jong Hee Hwang |
| Keywords | Composite, Cristobalite, Hexacelsian, Interphase, Microcrack, Transformation |
| Price | US$ 28,- |
A new concept for achieving graceful failure in oxide composites is introduced. It is based on crack deflection in a weak interphase between a matrix and reinforcement (e.g. fiber), or in a laminated composite. The interphase can be phase transformation weakened by volume contraction and/or unit cell shape change. Microcracking induced by a displacive, crystallographic phase transformation in silica-based interphases resulted in increase in the toughness of the bulk composites. In the present study, mullite/cordierite laminates with b®a-cristobalite (SiO2) transformation weakened interphase, and alumina matrix fibrous monolith with metastable hexacelsian (BaAl2Si2O8) interphases were investigated for interphase debonding behavior. In mechanical test, the laminates showed step-wise load drop behavior dependent on a grain size of b-cristobalite. In particular, in the fibrous monolith design, the load-deflection curve showed unusual plastic-like behavior with reasonable work of fracture.