The effects of ultra-high-gravity field on phase transformation and microstructure evolution of the TiC–TiB2 ceramic fabricated by combustion synthesis

Abstract

By applying combustion synthesis in high-gravity field, the TiC–TiB2 ceramic composites were prepared under different gravitational conditions from 500g to 2500g. XRD, FESEM and EDS results showed that there is no significant change in phase composition of TiC–TiB2, but a remarkable decrease of Al2O3 inclusions with the high-gravity field increased. Meanwhile, the well-developed faceted TiB2 grains with narrow size distribution were observed. Therefore, it can be proposed that the ultra-high-gravity field not only enhances the Al2O3 liquid separation from TiC–TiB2 liquid during the combustion synthesis process, but also promotes the microstructure refinement of the reaction products. The results of the mechanical test showed that the mechanical performance of TiC–TiB2 ceramic can be improved by increasing high-gravity field, especially its relative density, fracture toughness and bending strength.