Future trends for aircraft structural materials

Until the middle of the eighties, which corresponds to the launch of the A330/A340 Airbus programme, the search for improved performance - lower weight, reduced fuel consumption was pushing the development and the evaluation of new materials : polymeric matrix composites or aluminium-lithium alloys, for instance. Nowadays the situation has changed and, in a more and more competitive economical environment, the main criterion is cost reduction. This implies a new behaviour in the research and development teams, not only at the aircraft manufacturers, but also at the suppliers and at the institutes or universities. This paper illustrates this new trend through a review of the developments carried out during the last 2 decades and a critical analysis of the possible future evolution in the field of materials for civil aircraft applications. Most of the examples given come from the Airbus and ATR experience, with, however, a specific chapter dedicated to the future Supersonic Civil Transport Aircraft. The main families of materials which are addressed are aluminium alloys, carbon fibre reinforced plastics (carbon epoxy from the 1st and second generation, BMI, thermoplastics), high resistance stainless steels, titanium alloys (Ti 6-4 and the new beta high resistance alloys) and Metal Matrix Composites.