Comprehensive review on fabrication methods of metal matrix composites and a case study on squeeze casting

Use of metal matrix composites (MMCs) in automobile and aerospace industries is increasing predominantly since the last few decades, because of their logical amalgamation of properties, principally high strength and low weight. Though selection of matrix and reinforcements are the primary decisive factors of composite properties, the effect of fabrication method on its properties cannot be ignored. Accordingly, this paper accentuates a comprehensive review on different fabrication methods of MMCs as adopted by researchers in open literature. Outcome of the study revealed existence of three broad categories of composite fabrication methods, i.e. liquid state processing, semi-solid processing and solid state processing. However, many researchers have modified these methods suitably to achieve uniformity in reinforcement dispersion and enhanced properties. A case study on squeeze casting route to fabricate and investigate the microstructure and properties of Al 7075 base alloy and nano-TiB2 reinforced Al 7075 MMC is also emphasised in this paper. Results of the case study implied that the fabricated MMC was with very low porosity content (0.106%), near uniform distribution of reinforcements along with some segregated TiB2 regions in its microstructure. The MMC possessed higher mechanical properties (microhardness, tensile strength and compressive strength) than those of the base matrix alloy.