Microstructure evolution of Cu-TiC composites with the change of Ti/C ratio

Abstract

In this work, Cu-TiC composites have been successfully prepared by adding Ti and carbon black powder mixture into Cu melts. The microstructure evolution of the composites with the change of Ti/C ratio and its mechanism has been investigated. It is found that when Ti and carbon black powder mixture is added into Cu melts, Ti will react with carbon black to form TiC, which makes the carbon black be wetted. Then the unreacted Ti will be dissolved and further reacted with the wetted carbon black to form more TiC. However, the formed TiC particles are dispersed difficultly and tend to aggregate into agglomerations. Increasing the Ti/C ratio is an effective method to improve the distribution of TiC. It is found that, comparing with the Cu-4Ti-1C, non-stoichiometric TiCx with smaller x which has the better wettability with Cu melts can be synthesized in the Cu-5Ti-1C and Cu-6.67Ti-1C. As a result, TiC particles are more uniformly distributed in the prepared Cu-Ti-C composites with higher Ti/C ratio.