Determination of interfacial mechanical properties of ceramic composites by the compression of micro-pillar test specimens

Chunghao Shih, Yutai Katoh, Keith J. Leonard, Hongbin Bei, Edgar Lara-Curzio

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24 Scopus citations

Abstract

A novel method to determine the fiber-matrix interfacial properties of ceramic matrix composites is proposed and evaluated; where micro-pillar samples containing inclined fiber/matrix interfaces were prepared from a SiC fiber-reinforced SiC matrix composites and then compression-tested using the nano-indentation technique. This new test method employs a simple geometry and mitigates the uncertainties associated with complex stress state in the conventional single-filament push-out method or tensile unloading-reloading hysteresis loop analysis method for the determination of interfacial properties. Based on the test results using samples with different interface orientations, the interfacial debond shear strength and the internal friction coefficient are explicitly determined and compared with values obtained by other test methods. SEM observation showed that micro compression caused an adhesive type of debonding between the fiber and the pyrolytic carbon interface. The results suggest that the debonding/failure behavior of the micro-pillars followed the Coulomb fracture criterion. The determined interfacial debond shear strength is ~100 MPa, which appears to be smaller than that determined from fiber push-out test for similar composite systems. The difference can be explained by the effect of normal stress (clamping stress) on the apparent interfacial debond shear strength.

Original languageEnglish
Pages (from-to)5219-5224
Number of pages6
JournalJournal of Materials Science
Volume48
Issue number15
DOIs
StatePublished - Aug 2013

Funding

Acknowledgements This work was sponsored by the Office of Fusion Energy Science, US Department of Energy under contract DE-AC05-00OR22725 with UT-Battelle, LLC. The authors would like to thank Mr. Wallace Porter for useful discussions and help on sample preparation. The authors would also like to thank Dr. Peter J. Blau for reviewing the manuscript.

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