CHARACTERIZATION OF FIBER MATRIX INTERFACES IN COMPOSITES WITH A BORON-NITRIDE MATRIX/

The fracture behavior of boron nitride (BN) composites reinforced with several types of carbon and ceramic fibers has been examined. Fiber p roperties and fiber/matrix interface characteristics were found to con trol the mechanical strength and toughness of the composites. Transmis sion electron microscopy demonstrated preferential orientation of the BN matrix parallel to the fiber surfaces. Auger electron spectroscopy was then used to examine the fiber/matrix interface and locate the pat h of interface debonding. Single-fiber-push-out experiments were used to quantify the mechanical properties of the fiber/matrix interface. T he bulk composite fracture properties were consistent with current und erstanding in that a lower interfacial toughness was found to enhance fiber pull-out and increase the composite toughness. Matrix abrasion d uring fiber sliding had a significant effect on the sliding behavior o f the fibers. (C) 1996 Published by Elsevier Science Limited