Progress towards a micro fibre push-out method for measuring fibre-matrix interface properties in SiC composites
Experiments and finite element modelling have been used to explore a method for miniaturising fibre push-out testing to the scale of thin ion irradiated layers. Correlation of interfacial surface area to debond stress has been identified for short fibres, and is related to a size effect following a Weibull distribution. Weibull analysis may be used to provide size-independent interfacial properties for use in engineering scale models. Various parameters have been assessed for their relative importance: axial misorientation of fibres appears to have a negligible effect on push-out characteristics while the taper of fibres does not alter the debond stress, but does alter the frictional component of micro push-out tests. Micro push-out testing directly measures properties of the interface, unlike in long fibre push-out testing, where fracture occurs locally and propagates along the interface, so debond stress as a material property is not directly measurable without assumptions or analytical adjustments.