| About this Abstract |
| Meeting |
Materials Science & Technology 2020
|
| Symposium
|
Ceramic Matrix Composites
|
| Presentation Title |
Properties of Thermally Grown Borosilicate Glasses and Their Impact on CMC Oxidation and Life Prediction |
| Author(s) |
Kaitlin Detwiler, Bohuslava McFarland, Megan Watza, Elizabeth J. Opila |
| On-Site Speaker (Planned) |
Elizabeth J. Opila |
| Abstract Scope |
SiC/BN/SiC composites rely on the BN matrix/fiber interphase for achieving the requisite composite toughness for load-bearing applications, such as turbine engine components. In high temperature oxygen- and water vapor-containing conditions relevant for combustion environments, the BN and SiC phases oxidize to form B2O3 and SiO2, respectively. These oxides in turn combine to form a borosilicate glass. The properties, distribution, and morphology of the borosilicate glasses vary considerably over the range of relevant operating conditions. Viscosity changes by orders of magnitude as a function of composition and temperature. The composition, in turn changes dramatically with temperature and gaseous environment. Finally, the tendency for boria dissolution of SiC leading to rapid SiC fiber degradation also depends on temperature and silica content. Results from laboratory furnace CMC studies in combination with properties available in the literature are reviewed. Implications of the wide range of borosilicate properties on life prediction of SiC/BN/SiC are discussed. |