The effect of spark plasma sintering parameters on the densification and mechanical properties of TiB₂-TiC-TiB composites

Spark plasma sintering (SPS) tests were designed using the Taguchi method to create high-performance composites consisting of 60 wt% TiB₂, 30 wt% TiC, and 10 wt% Ti. The effects of SPS parameters on the microstructure and mechanical properties of TiB₂-TiC-TiB composites were systematically investigated. Additionally, the evolution of phase and microstructure during the densification of the composites was analyzed in detail. It has been demonstrated that composites can achieve a high relative density of 99.8%, a hardness of 22.2 GPa, a strength of 739 MPa, and a fracture toughness of 7.07 MPa m^1/2, as well as a dense structure and small grain size. These properties can be obtained by sintering at a temperature of 1500°C, a pressure of 50 MPa, and a holding time of 5 min. Sintering temperature is the primary factor that promotes the densification of the composite and influences its relative density, grain size, and morphology. Holding time and sintering pressure are relatively minor factors, but they play important roles at different stages of the sintering process.