Reactive spark plasma sintering of ZrB2-TiC composites: Role of nano-sized carbon black additive

ZrB2-TiC composites with and without nano-sized carbon black as the sintering additive were densified through spark plasma at 1900 °C for 7 minutes under applied pressure of 40 MPa. The role in densification behavior, phase arrangement, microstructural characteristics mechanical properties sintered then investigated. While both composite samples found to be fully sintered, thermodynamic reactive was also studied. Results indicated that whereas process leads complete consumption TiC formation solid solution matrix samples, presence initial composition can result remained final microstructure. Besides in-situ synthesized zirconium carbide major reinforcement phase, such a lead significantly different behavior composites. Accordingly, hardness 21.8 24.3 GPa indentation fracture toughness 3.3 4.5 MPa.m0.5 obtained carbon-black free doped respectively. densification, hardening, toughening mechanisms finally discussed.