Interaction mechanisms between ceramic particulates and metallic matrices, and mechanical behavior of aluminum-silicon-X(X = silicon carbide, titanium diboride) MMCs synthesized using spray atomization, co-injection and deposition

Al-Si based composites (bulk materials and droplets) were prepared containing particulate reinforcements such as SiC and TiBTheoretical models were developed to study the penetration behavior of ceramic particulates into metallic droplets and the rejection/engulfment behavior of ceramic particulates by the solid/liquid front. It was found that the penetration ability of ceramic particulates that are normally encountered in Al-based MMCs decreases in the following sequence: TiBThe microstructures of the spray deposited MMC bulk materials were compared to those of unreinforced matrix alloys. The results showed a significant modification in the microstructure of the as-spray deposited materials due to the incorporation of reinforcement particulates. The presence of reinforcement particulates reduced the grain size, and the size of the primary Si phase in the MMCs. Room temperature tensile tests revealed different strengthening behavior due to the addition of various particulates. Incorporation of SiC led to a significantly higher strength of Al-12Si/SiC over that of unreinforced Al-12Si in both the as-extruded and solution heat treated conditions. Moreover, incorporation of TiB...