The microstructures of in-situ synthesized TiC by Ti-CNTs reaction in Cu melts

In order to study the influence of the carbon nanotubes (CNTs) as a source of carbon on the microstructure of in-situ synthesized TiC in Cu melts, CNTs and Ti powders were introduced into melted Cu to prepare TiC-reinforced Cu matrix composites. The influence of Ti/C ratio and Si on the microstructures and properties of the composites were also examined. It is found that CNTs can be effectively wetted through the Ti-C reaction and successfully introduced into Cu melt to synthesize TiC. In examining the changes in Ti/C ratio, it was found that an increase in the Ti content may result in the decrease of TiC agglomeration and improvement of TiC dispersion, while simultaneously causing an increase in the TiC particle size. Besides, while the addition of Si into Ti-CNTs mixture can also improve the distribution of TiC, the effect is weak compared with that of increasing the content of Ti. It was also found that the highest hardness (238.8 HV) is achieved by the Cu-Ti-C composite with the highest Ti/C ratio, while the electrical conductivities of all the prepared composites are relatively low, which should be due to the insufficient reaction between Ti and CNTs.