The effects of CeO₂ on the microstructure and synthesis mechanism of Al-Ti-C alloy were investigated by quenching experiment method, while using Al powder, Ti powder, graphite powder, and CeO₂ powder as main raw materials. The results showed that the addition of CeO₂ was favorable for promoting the formation of TiC particles in Al-Ti-C systems. With CeO₂ contents increasing, the distribution of TiC particles were more homogeneous, and the rare earth phase Ti₂Al20Ce was formed. CeO₂ had little effect on the synthesis of Al₃Ti particles in Al-Ti-C systems, but had a significant effect on the synthesis of TiC particles. In the Al-Ti-C system, TiC is mainly formed by the reaction of dissolved [Ti] and solid C in the melt. While in the Al-Ti-C-Ce system, CeO₂ reacts with C and O₂ to form CeC₂ firstly, and then CeC₂ reacts with dissolved [Ti] to form TiC. Based on thermodynamic calculation and microstructure analysis in the process of reaction, a macroscopic kinetic model of Al-Ti-C-Ce system reactions was proposed in this paper.
Keywords: Al-Ti-C alloy; CeO2; microstructure characteristics; quenching experiment; synthesis mechanism.