Intermetallic-matrix composites - A review

With properties lying between those of metals and ceramics, intermetallic compounds are particularly attractive for high temperature structural applications. Considerable progress has been made in improving the ductility of these rather brittle materials, especially with the titanium aluminides Ti3Al (alpha-2) and TiAl (gamma). But monolithic intermetallic compounds are unlikely to have the right combination of ambient temperature ductility and high temperature strength for the most demanding aeroengine applications. Further progress depends on the development of engineered composite materials, which exploit the combined potential of ceramics, intermetallics and metals to give a desirable balance of properties. This paper reviews developments in intermetallic matrix composites (IMCs), concentrating on the last four years and drawing examples from the three most widely researched matrix systems: titanium aluminides, nickel aluminides and molybdenum disilicide.