Processing of Carbon Fibre Reinforced Copper Based Composites with Chromium Additions for Control of Interface Adhesion

Abstract

A new method has been devised for the processing of composites consisting of a copper alloy matrix reinforced by carbon fibres. The method involves the incorporation of the carbon fibres in a foam made from an aqueous suspension of fine powders of the matrix constituents. After filtering, the composite is consolidated by hot pressing. Microstructural analysis reveals a uniform fibre dispersion with little fibre contact or porosity. Owing to the large thermal expansion mismatch and the low chemical affinity between copper and carbon, subsequent exposure to high temperature causes interface decohesion with the formation of cavities around the fibres by coalescence of the decohered areas. Interface adhesion can be improved by chromium additions which bring about the formation of a carbide interlayer between the carbon fibres and the copper base matrix. PM/0557