Metal and Intermetallic Matrix In-Situ Particle Composites

The processing methods for the discontinuously reinforced composites with metal and intermetallic matrices, and the resulting properties, are reviewed. These composites have distinct advantages over the conventional composites. Studies on both liquid phase and solid phase composites have been reported in the literature. The objective of trying different processing methods is to in-situ produce particle reinforced composites based on metal and intermetallic matrices. The matrix materials used are aluminum, Al compounds, Ti compounds, copper, magnesium, manganese, and titanium. The particulate reinforcements used are TiO sub 2 , SiC, nickel aluminide, and MoSi sub 2 . In the liquid phase processes, solid, liquid, and gaseous phases are introduced into a liquid metal/alloy to react with the base metal or its alloying elements and hence to produce reinforcement phases. In solid phase processes, elements or elements/compounds are blended, compacted and heated at a selected temperature to form the desired reinforcements. Both techniques produce very fine reinforcements in the matrices. The interfaces are clean and are semicoherent in some cases. Mechanical properties of in-situ composites are comparable with or better than those of conventional composites.