The Effects of Cooling Holes on SiC/SiC CMC Tensile Strength

Abstract

Abstract Silicon Carbide fiber-reinforced Silicon Carbide (SiC/SiC) Ceramic Matrix Composites (CMCs) are currently operating in select high temperature components of turbine engines. Primary benefits of CMCs compared to metals are improved temperature capability, reduced cooling requirements and reduced component weight. High temperature materials require less cooling air to be diverted from the compressor, resulting in improved engine performance. However, some amount of film cooling may be necessary when CMCs are implemented in higher temperature applications. Film cooling requires holes to be fabricated at appropriate locations and orientations within these components. It is important to understand how such holes will affect the material properties. While previous studies have shown that CMCs are notch insensitive, the effect of multiple holes and different hole orientations on SiC/SiC CMCs is not well documented. This study examines the effect of cooling holes on SiC/SiC tensile properties. Several hole geometries fabricated in SiC/SiC samples are explored. Mechanical test data on specimens with multiple holes is reported for tensile loading at room temperature. Tools such as Digital Image Correlation (DIC) and Acoustic Emission (AE) are used to monitor strain and cracking in the CMC upon loading.