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Effect of Oxidation on Crack Deflection in SiC/Al 2 O 3 Laminated Ceramic Composites
Author(s) -
Krishnamurthy R.,
Rankin J.,
Sheldon B.W.
Publication year - 2005
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/j.1551-2916.2005.00320.x
Subject(s) - materials science , interphase , composite material , microstructure , deflection (physics) , composite number , ceramic , porosity , scanning electron microscope , optics , genetics , physics , biology
Laminated composites consisting of SiC and a thin porous alumina interphase were exposed to air at 500°C to produce a persistent, nearly uniform oxidation product layer. Crack deflection at the interface was then studied using a four‐point bend testing procedure and interfacial fracture resistances were found to decrease with increasing oxidation times. Electron microscopy observations of the fractured interface show a complex multi‐phase microstructure. These results show that oxidation can produce a sufficiently weak interface in a SiC‐porous alumina interphase composite, in contrast to most other SiC composites where interface oxidation produces a strongly bonded interface which inhibits crack deflection.