In-situ process for producing aluminium matrix composites containing intermetallic material

摘要

High modulus aluminium materials are of interest for many aerospace and automotive applications from the point of view of their ability to save weight and to overcome other mechanical design limit-ations. A class of materials having the ability to provide the required property improvements are metal matrix composites (MMCs), which are receiv-ing a lot of attention in the research community. Due to lower costs, easier fabrication and more isotropic properties, discontinously reinforced alu-minium using short fibres or particulates is especially attractive. Of the various ways of producing MMCs, the liquid metallurgy techniques, including the infiltration of a porous preform or the introduction of particles in the molten aluminium prior to its solidification, are largely developed due to their potential of being commercially economic processes on a large scale. Much effort has been oriented towards reinforcements made of ceramic (see for example [1]) or metallic [2] materials. Studies concerning MMCs reinforced by intermetallic com-pounds are very limited although they could have great potential. Intermetallic compounds based on aluminides are interesting because of their low density, good wear resistance and high oxidation resistance [3]. Unfortunately, brittle fracture and poor ductility have limited their use. However, the causes of their brittleness are now established and improvement in ductility has been achieved by ad hoc element additions [4].