Synthesis and applications of cast metal matrix composites and syntactic foams

Metal Matrix Composites (MMCs) are an important class of engineering materials in the present times. Most of their current applications are in ground transportation, aviation, electronics, thermal management, electrical transmission, and sports industries. Cost and tailorability of mechanical properties are two major challenges in achieving a widespread use of MMCs in industrial applications. Casting techniques are considered very attractive for bringing the cost of MMCs within the range where their mass applications can be developed. The present paper reviews different casting techniques for synthesizing MMCs and the issues related to solidification processing, mechanical properties of cast MMCs and their current and potential applications. Mechanical properties of MMCs are compared to a wide range of other engineering materials, including polymer matrix composites. A special class of MMCs containing hollow particulate reinforcements is also discussed. These composites, called syntactic foams, have potential applications due to their low density, energy absorption and damage tolerance. Properties of metal matrix and polymer matrix syntactic foams will be compared.