scanning auger microscopy (sam) has been used to study the fibre/matrix interface of composite materials. this novel application enables further understanding of the mechanism of failure in composites when applied to carbon fibre-reinforced epoxy material initial work was carried out on carbon fibres prior to their incorporation into the resin matrix. auger spectroscopy can be used to detect the presence of thin polymeric layers on the carbon fibres if a suitable, matrix-specific element is chosen to form the scanning auger image. two composite materials have been investigated. they differ from each other by their fracture mechanisms. in the case of unidirectional continuous fibre composites, a high volume fraction of conducting carbon fibres makes auger analysis possible although the failures surface is predominantly polymer residues. for short-fibre composites, the technique is more difficult considering the low volume fraction of fibres, but auger spectroscopy enables the identification of microfailure mechanism and the effect of fibre surface treatment on the failure mode. (edited author abstract) 5 refs