Tantalum carbide composites with 0.76-8.85 wt.% elemental silicon as a sintering aid were fabricated by spark plasma sintering (SPS) at 1700 degrees C and 30 MPa for 5 min. The transient-liquid-phase sintering behavior, the microstructures and the mechanical properties of the tantalum carbide composites were investigated. Oxide impurities present on the surfaces of the tantalum carbide particles were eliminated by reactions with the elemental silicon in a temperature range from 1271 degrees C to 1503 degrees C to benefit densification. Then the silicon melted at its melting point temperature of 1413 degrees C to facilitate rearrangement of the tantalum carbide particles. By the end of the densification, the elemental silicon transformed into more refractory TaSi2 and SiC in the consolidated ceramics by reactions with the tantalum carbide at temperatures lower than 1773 degrees C. Both TaSi2 and SiC particles improved densification by physically pinning growth of the tantalum carbide grains. Further densification was resulted from creep flow of the silicides after brittle-to-ductile transformation of the silicides at temperatures <1650 degrees C. Due to the good effects of using elemental silicon as the sintering aid, all the compositions reached densities >96.7% theoretical. The average grain sizes in the consolidated materials decreased with the silicon addition from about 19 gm in the 0.76 wt.% Si composition to about 9 gm in the 8.85 wt.% Si composition. A good flexural strength up to similar to 709 MPa was reached in the 8.85 wt.% Si material due to full density and fine microstructure. (C) 2014 Elsevier B.V. All rights reserved.