Determination of fibre-matrix interfacial properties in ceramic-matrix composites by a fibre push-out technique

Abstract

A simple concentric cylinder model is developed for the fibre push-out test in order to interpret the experimentally observed indenter load-displacement curves in ceramic-matrix composites. The fibre-matrix interface is assumed to be partially bonded and partially frictionally coupled. It is shown that a slope change in the loading curve corresponds to bonding at the fibre-matrix interface. In contrast an insignificant change in the slope is predicted for composites in which the fibre-matrix interface is frictionally coupled. This model also provides a framework for determining the interfacial debond energy and the interfacial shear strength in ceramic composites using the fibre push-out tests. The predictions of this model are compared with the push-out test results performed on zircon-SiC composites uniaxially reinforced with either uncoated or BN-coated SiC monofilaments, which suggested that the fibre-matrix interfaces in both of these composites are frictionally coupled.