The effects of ultra-high-gravity field on phase transformation and microstructure evolution of the TiC-TiB_2 ceramic fabricated by combustion synthesis

摘要

By applying combustion synthesis in high-gravity field, the TiC-TiB_2 ceramic composites were prepared under different gravitational conditions from 500 g to 2500 g. XRD, FESEM and EDS results showed that there is no significant change in phase composition of TiC-TiB_2, but a remarkable decrease of Al_2O_3 inclusions with the high-gravity field increased. Meanwhile, the well-developed faceted TiB_2 grains with narrow size distribution were observed. Therefore, it can be proposed that the ultra-high-gravity field not only enhances the Al_2O_3 liquid separation from TiC-TiB_2 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-TiB_2 ceramic can be improved by increasing high-gravity field, especially its relative density, fracture toughness and bending strength.