Metal matrix composites (MMCs) are currently receiving a great deal of attention due to high modulus and strength, wear resistence and thermal stability, which make them very attractive for use in automotive and aerospace industry. Interfacial shear strength (IFSS) between fiber and matrix is one of the most important factors in characterizing the mechanical properties of fiber reinforced composites. Several micro-mechanical techniques were proposed for measuring the IFSS in fiber reinforced composites. Some of the most frequently used techniques include the single fiber pull-out test, the single fiber composites (SFC) test, and the microindentation method. Among them, the SFC test method, originally proposed by Kelly and Tyson for the application to the fiber/metal composite system, is to give comparatively abundant information (e. g. the interfacial failure mode as well as the IFSS) using only several specimens. In this study, the SFC test with the aid of acoustic emission (AE) technique has been conducted to evaluate the IFSS and micro- failure mechanism of SiC single fiber reinforced metal matrix composite. Dog-bone shaped single fiber composite specimens were fabricated for this purpose. AE signals were detected by a wide band type sensor with maximum sensitivity of -60 dB at 550 kHz. The sensor output was only amplified by 60 dB at preamplifier then fed into an AE signal processing unit, Locan AT, where AE parameters were extracted. Monitoring of AE signals during straining SFC specimens showed the sequential occurrence of three distinct groups of AE data. First two groups are associated with matrix cracking and partial fiber debonding and the third group is mainly attributed by fiber breakage. By setting the appropriate threshold level during the AE measurement, low energy AE data associated with matrix cracking can be filtered off to obtain the AE data with high energy due to mainly fiber fracture. This AE method can be correlated successfully to the fragmentation technique to measure the IFSS by counting average number of fiber breakage.
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