In this work, graphite and diamond are successfully introduced into Al melts and TiC is in situ-synthesized based on reactive wetting. It is found that the microstructures of the prepared TiC-reinforced Al composites are varied with the change in carbon sources and their sizes. TiC particles tend to form agglomerations in the composites prepared by both graphite and diamond, but the size of the TiC particles as well as their agglomerations will decrease with the decrease in the carbon source size. In addition, the Ti-C reaction is also difficult to fully carry out due to the influence of the Al-C reaction. As a result, in addition to TiC particles, Al4C3 will also be present in the composites prepared by graphite, especially when the size of graphite is large. As for the composites prepared by diamond, diamond@Al4C3@TiC core-shell particles will form when the size of the diamond is large, such as 10 μm in this work, and these particles will transform into Al4C3@TiC core-shell particles when the size of the diamond is decreased.
Keywords: Al matrix composites; diamond; graphite; reactive wetting.