DISCONTINUOUSLY REINFORCED INTERMETALLIC MATRIX COMPOSITES

Intermetallic matrix composites have recently received considerable attention as potential candidates for high-temperature applications. A variety of matrices and reinforcements have been examined to date, and reinforcement type, volume fraction, size, shape, and distribution have been shown to affect microstructure and mechanical properties. Several innovative approaches have been devised to produce discontinuously reinforced composites, ranging from such conventional techniques as blending, mechanical alloying, and rapid solidification processing to more exotic techniques, such as reactive consolidation and XD(TM) technology, which depend on the exothermic heat of formation of compounds. Composite mechanical properties of interest typically include high-temperature strength, the strain-rate dependence of strength, and ambient-temperature toughness and/or ductility. Thermodynamic stability of the reinforcement, elastic modulus mismatch with the matrix, and differences in thermal expansion coefficient between the matrix and reinforcement influence these properties. This paper addresses recent advances in these areas.