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Optimizing the fiber push‐out method to evaluate interfacial failure in SiC/BN/SiC ceramic matrix composites
Author(s) -
De Meyere Robin M. G.,
Gale Louise,
Harris Stephen,
Edmonds Ian M.,
Marrow Thomas J.,
Armstrong David E. J.
Publication year - 2021
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.17673
Subject(s) - materials science , composite material , interphase , fiber , ceramic , ceramic matrix composite , silicon carbide , microscale chemistry , genetics , mathematics education , mathematics , biology
The investigation of several parameters during fiber push‐out micromechanical tests on the interfacial shear strength (ISS) of the BN interphase in SiC f /SiC ceramic matrix composites (CMC) was undertaken to optimize experimental work. The SiC f /SiC composites—candidate materials for jet engine components—were manufactured with varying fiber types and interlayer thicknesses. Experimental parameters explored included analyzing the effect of sample thickness on the success rate of micromechanical tests, the effect of fiber local environment whether at tow‐level (intra‐tow variability in ISS) or CMC architecture‐level (inter‐tow variability), the effect of nanoindenter flat‐punch tip size, and the effect of the interphase thickness itself. Over 1000 fiber push‐outs were performed and analyzed in this work—with data presented as cumulative distribution functions to compare and contrast samples. It was found that the ISS measured was strongly and statistically influenced by the underlying fiber roughness (interphase adherence), as well as its local fiber environment (e.g., number of nearest neighbors) only if the thickness of the interphase itself surpassed a threshold of 200 nm. Finally for thinner interphases, limited value was added to the CMC as the ISS measured was high and there was no effect from any local environment.