Extensive research activity, over the last 15 years, has been conducted on structure/property relationships and processing of intermetallic compounds for high temperature use. Progress has been made in improving a number of properties of these compounds; however, the demanding balance of properties required (high strength, good strength retention at temperatures exceeding 1000°C, low density, damage tolerance at ambient temperatures, good creep and stress rupture characteristics and environmental stability at high temperatures) are not likely to be achieved in a monolithic (single phase) compound.
Initial work on intermetallic matrix composites has proven to be quite promising. It has already been shown that compounds, brittle at room temperature, may be toughened by the inclusion of appropriate reinforcements, either strong or tough and ductile. Both artificial and natural or in-situcomposite fabrication techniques have been used to manufacture these composite systems. The properties of two specific intermetallic matrix composite systems, NiAl/Al2O3 and Cr2Nb/Nb are summarized to elucidate their strengths, weaknesses and potential. Candidate composite systems are also discussed along with the rationale behind their selection.