Microstructure and mechanical properties of the spark plasma sintered TaC/SiC composites

TaC/SiC composites with 5-40 vol.% 6H-SiC were fabricated by spark plasma sintering at 1800 degrees C for 5 min. Effects of SiC concentrations on the densification, microstructure, and mechanical properties of the materials were investigated. The results showed the densification process of the TaC/SiC composites was composed of six sequent stages. SiC addition was effective in eliminating the closed porosities in the final stage to yield fully dense TaC/SiC composites at 20 vol.% SiC concentrations and above. TaC grain sizes decreased with SiC concentration increase. The 40 vol.% SiC composition had the highest flexure strength and fracture toughness up to 703 MPa and 6.8 MPa m(1/2) due to the reinforcement of the SIC agent. The TaC/SiC composites with 20 and 40 vol.% SiC showed good flexural strength at 1400 degrees C. (C) 2011 Elsevier B.V. All rights reserved.