The objective of this project is to improve the fundamental understandi of the fracture mechanics and fatigue of ceramic matrix composites at room temperature and in the temperature range 800 - 12000C. This will be done by characterizing and quantifying the behaviour of matrix cracks using new techniques being developed at QMW. It will be possible to investigate directly the effect of monotonic and cyclic loading on cracks. Unidirectional and cross-ply SiC fibre (Tyranno) reinforced glass ceramic matrix (osumilite) composites will be studied. The project is a logical extension of research currently being performed at QMW on particulate ceramic composites (Brite-Euram Project No BRE2-CT94-0613, "Development of High Temperature Creep, Fatigue and Thermal Shock Resistant Zircon and Mullite Zircon Ceramics"). The results and observations from this research will provide a solid base of fundamental knowledge for the development of consistent and comprehensive models to predict the o-e (strength) and S-N fatigue behaviour of CMCs.