Enhancing Reinforcing Efficiency of SiC Particles in Aluminum Matrix Composites with Intercalated Oxygen Atoms

In metal matrix composites (MMCs), the interface between the metal matrix and reinforcement critically influences mechanical properties of MMCs because the load can transfer at the interface via the interfacial shear stress. We develop a new aluminum matrix composite (Al-O/SiC composite) reinforced with silicon carbide (SiC) particles which are dispersed in an interstitial aluminum alloy (called as I-Al) matrix containing oxygen atoms. The new composites reinforced with SiC particles are fabricated via powder metallurgy. Mechanical milling induces uniform dispersion of SiC particles in the matrix and also enables oxygen in the I-Al to be redistributed in the composite powder. Oxygen is observed at the interface between the matrix and SiC particles in the Al-O/SiC composite. Oxygen at the interface can provide additional chemical bonding other than mechanical interlocking at the interface, improving interface bonding of the composites. With the same amount of SiC particles, the mechanical properties of the Al-O/SiC composites including Vickers hardness, compressive yield strength, and elastic modulus are enhanced as compared to those of the Al/SiC composites. Therefore, the intercalated oxygen contributes to increasing reinforcing efficiency of the Al-O/SiC composites.