The Microstructures of TiC-Ti5Si3-Reinforced Cu Matrix Composites Prepared by Ti-SiC Reaction

In this work, the TiC and Ti5Si3-reinforced Cu matrix composites with different contents were successfully prepared through Ti-SiC reaction in Cu melts; accordingly, the microstructures of them were studied, and the hardness of the composites was tested. It is found that the synthesized TiC are granular, with a size ranging from 0.5 mu m to 3 mu m, while the Ti5Si3 are rod-like hexagonal prisms with a diameter of about 1 mu m and a length-to-diameter ratio of about 5 similar to 25. In addition, it is noticed that many Ti5Si3 rods are actually Cu@Ti5Si3 core-shell structure rods. TiC and Ti5Si3 alternately distribute in the Cu matrix to form the hybrid reinforcement system. With the increase in Ti-SiC content, the TiC particles, Ti5Si3 rods and Cu@Ti5Si3 increased obviously, and the solid skeleton structure of TiC-Ti5Si3 was formed. The hardness of the composites was 2.2 to 2.74 times greater than that of the as-cast pure copper. It is deduced that, compared to the composites reinforced by either TiC or Ti5Si3, the formation of the TiC-Ti5Si3 hybrid system is more helpful for improving the properties of the composites due to the different morphologies of TiC and Ti5Si3.