The Microstructure and Mechanical Properties of Mullite-Zirconia Composites

Mullite and mullite-zirconia (10 or 17 vol. %) composites with a range of density have been prepared by sintering at different temperatures. The strength and fracture -toughness have been measured. The composites, if compared with pure mullite, show a substantial strengthening (especially at lower density) and toughening . Because the KIC values have a little variation over a wide range of tetragonal content, a more complex toughening mechanism than stress-induced transformation is suggested.