Processing of advanced continuous fibre composites: Current practice and potential developments

Abstract

Current manufacturing routes for advanced continuous fibre composites are compared. The different routes lead to significant differences in the deformation required to consolidate the composite and in the fibre distribution in the composite. Excessive deformation increases the chances of fibre breakage or fibre surface damage and with non-uniform fibre distribution adversely affects composite mechanical properties. A new route for making composites is described which involves coating the fibre with the matrix by physical vapour deposition (PVD) before consolidation. Examples of Ti alloy, Al alloy, and Ti aluminides made by this route are given. It is shown that the PVD route may have many important advantages over alternative routes. It would enable a wide range of composites to be produced with precise control over matrix composition, matrix microstructure, fibre distribution, and fibre volume fraction. This could lead to increased toughness in intermetallic and ceramic composites. The PVD route also may allow composites to be made based on amorphous metal and superconducting ceramic matrices. The potential specific mechanical properties for crystalline and amorphous metal, intermetallic, and ceramic matrix composites are compared at room and at elevated temperatures. The factors that contribute to the cost of these composites are summarised. It is concluded that the cost/benefit assessment will be critical for the future development of continuous fibre composites.