R-Curve Behavior of Si3N4-BN Composites

초록

Si3N4-BN Composite materials are well known as one of the machinable ceramics, which can be easily machined with hard-alloy cutting tools. This composite possesses relatively high strength and temperature resistance, but can be machined without expensive diamond tools owing to the soft BN particles in the composites. In this study, R-curve behavior of the Si3N4-BN composites has been investigated to understand its machinability. It was shown that the R-curve rose slowly for this material so that the fracture toughness was low at small cracks but high at long cracks. This slowly rising R-curve behavior seems to enhance the machinability of this composite and to minimize the machining damage.