INTERFACES IN COMPOSITE MATERIALS

The mechanical functions of the fibre/matrix interlayer as well as its quantitative parameter dependencies and their influence on the properties of the composite system are discussed, with the theoretical model being considered under realistic conditions. Corresponding to that a number of in- terface structure phenomena of some advanced composite materials, revealed by high voltage and high resolution electron microscopy, are discussed with respect to their relevance to the control of composite properties, includ- ing complex interlayer systems, which are produced by fibre coating as well as by chemical solid state transport and exchange reactions. The effects of hooking-together, binding, internal microcracking, and sublayer formation . are demonstrated, and in some cases correlated with the mechanical be- haviour of the materials as revealed by in situ tensile tests. PACS numbers: 61.16.Bg, 68.35.Fx, 81.60.Dq