In Situ Preparation of TiC x Particles with Different Sizes and Self-Assembly Behavior Analysis of TiC x /Al-Bi Alloy

In this paper, TiC x particles were prepared by an in situ process and added to an Al-Bi alloy, and the effects of TiC x particles on the homogenization preparation and refinement mechanism of Al-Bi alloys were studied. The TiC x particle size can be greatly reduced by decreasing graphite particle size, and the TiC x particle size was further reduced after changing C source from graphite to MLG. The TiC x particle gradually changed from angular octahedral to truncated octahedral and then became round with the C/Ti ratio increasing from 0.4 to 1.0. After the TiC x particles being added to the Al-Bi alloy, it was found that TiC x had a significant inhibitory effect on the macrosegregation and coarsening of Bi phase. The average diameter of the Bi phase decreased from 4.32 μm to 3.45 μm with the TiC x particle size decreased, and the distribution became more dispersed and uniform, contributing to the heterogeneous nucleation and self-assembly behavior of TiC x particle. With the decreasing of TiC x particle size, the refinement mechanism evolved from heterogeneous nucleation to self-assembly.