Optimizing the fiber push‐out method to evaluate interfacial failure in SiC/BN/SiC ceramic matrix composites

The investigation of several parameters during fiber push-out micromechanical tests on the interfacial shear strength (ISS) BN interphase in SiCf/SiC ceramic matrix composites (CMC) was undertaken to optimize experimental work. composites—candidate materials for jet engine components—were manufactured with varying types and interlayer thicknesses. Experimental explored included analyzing effect sample thickness success rate tests, local environment whether at tow-level (intra-tow variability ISS) or CMC architecture-level (inter-tow variability), nanoindenter flat-punch tip size, itself. Over 1000 push-outs were performed analyzed this work—with data presented as cumulative distribution functions compare contrast samples. It found that ISS measured strongly statistically influenced by underlying roughness (interphase adherence), well its (e.g., number nearest neighbors) only if itself surpassed a threshold 200 nm. Finally thinner interphases, limited value added high there no from any environment.