Fabrication of Ceramic Matrix Composite Tubes Using a Porous Mullite/ Alumina Matrix and Alumina/Mullite Fiber

摘要

Continuous fiber ceramic composites show promise for applications in high-temperature oxidizing environments, but their actual use has been limited in part due to unstable non-oxide-based constituents or from inadequate oxide- based ones. A porous mullite/alumina matrix combined with alumina/mullite fiber reinforcement eliminates the need for an interface coating while producing a strong, tough and oxidation resistant composite. In this study, a fiber-matrix prepreg was produced by infiltrating Nextel 720 cloth with a filter-pressed mullite/alumina slurry through a VibroIntrusion process. This prepreg was used to fabricate thin-walled tubes, which were then pressure burst tested to failure. Post-test evaluation of the tubes and a finite element analysis show that the tubes failed from excessive interlaminar shear stresses. The implications of these results and the utility of the fabrication method used in this study are discussed.