Spark plasma sintering of B₄C-TiB₂-SiC composite ceramics using B₄C, Ti₃SiC₂ and Si as starting materials

Almost fully dense B₄C-TiB₂-SiC composite ceramics with high flexure strength and good fracture toughness were fabricated through in-situ reaction between B₄C, Ti₃SiC₂ and Si using spark plasma sintering method at a relatively low temperature of 1650 °C. The intergranular and intragranular structure containing nanoparticles with different phase were introduced into the composite ceramic. The nano and micro particles in the microstructure formed a multi-scale particles reinforced structure. The refined matrix grains and the multi-scale reinforcing particles had a synergetic effect on improving the mechanical properties of the composite ceramics. As a result, B₄C-TiB₂-SiC composite ceramic with 30 wt% (TiB₂ + SiC) exhibits low density and optimum mechanical properties with high flexural strength of 531.2 MPa, good fracture toughness of 5.77 MPa m^1/2 and moderate micro-hardness of 28.6 GPa.