Effect of thermal cycling on the microstructure of continuous carbon fibrereinforced copper matrix composites

Copper reinforced by continuous carbon fibres is a candidate material for h eat sinks of electronic modules. The thermal expansion can be matched to th e adjacent ceramics and the thermal conductivity is higher than that of alt ernative materials. Because the material is expected to work in cyclic ther mal conditions during application its structure must withstand such a load without any severe damage. The structure of unidirectionally and cross-ply fibre reinforced samples was observed before and after thermal cycling by o ptical microscopy and Scanning Electron Microscopy (SEM). SEM was used for examining the fibre-matrix interface before and after thermal cycling. Opti cal microscopy showed the arrangement of individual monolayers. The influen ce of adding copper foils between individual monolayers on the structure of the material is reflected in a reduction in the number of cracks in monola yers. (C) 1999 Elsevier Science Ltd. All rights reserved.