Influence on TiC microstructure from different synthesis processes in the Cu–Ti–SiC system

Abstract

In this study, the formation processes of TiC in a Cu–Ti–SiC system following the addition of a Ti–SiC mixture into a Cu melt were studied by analyzing the reaction intermediates, and the influence of the synthesis processes on the TiC microstructure was examined. It is found that, upon the addition of Ti–SiC into the Cu melt, the reaction of Ti and Cu to form a Cu–Ti liquid phase occurred first, followed by the reaction between liquid Ti, denoted as Ti(l), and SiC. However, the Ti(l)–SiC reaction processes vary depending on the reaction conditions and significantly influence the microstructures of the TiC particles, especially their dispersion in the Cu matrix. Under certain conditions, such as a lower reaction temperature and larger SiC size, SiC does not directly react with Ti(l). It first transforms into graphite through the outward diffusion of Si; subsequently, the graphite phase reacts with Ti(l) to form TiC. In this case, the synthesized TiC particles tend to connect with each other to form agglomerates. Under conditions conducive to the direct reaction of the Ti(l)–SiC system, such as a higher reaction temperature and smaller SiC size, Ti(l) and SiC first react to form a Ti3SiC2 phase that then decomposes into TiCx and Ti–Si phases and eventually transforms into TiCy (x > y) and amorphous or crystalline Si. In this case, the formed Ti–Si or Si phase can prevent the agglomeration of TiC particles, leading to their more uniform distribution in the prepared Cu matrix composite.