Effect of TaC Content on Microstructure and Properties of W-TaC Composites

Transition metal carbide reinforcement can improve the performance of pure W. W-(10-50) vol% TaC composites were prepared by spark plasma sintering at 2100 degrees C. The effect of TaC content on the microstructure, mechanical properties, and thermal conductivity of the composites was studied. The ablation resistance of the W-TaC composites was evaluated under an air plasma torch. The addition of TaC into the W matrix enhanced the densification of W-TaC composites, the density of W-40 vol% TaC composite exceeded 93%. TaC particles inhibited the growth of W grains during sintering. Reactive diffusion occurred between W and TaC, forming the solid solutions of (W,Ta)(ss) and (Ta,W)C-ss. W and TaC react to form the W2C phase at a TaC content of 50 vol%. The Vickers hardness of the composite increases from 3.06 GPa for WTA1 to 10.43 GPa for WTA5. The flexural strength reached 528 MPa in the W-40 vol% TaC composite. The thermal conductivity of W-20 vol% TaC composite was 51.2 +/- 0.2 W center dot m(-1)center dot K-1 at 750 degrees C. The addition of TaC improved the ablation resistance of W-TaC composites. The mass ablation rate of W-30 vol% TaC composite was 0.0678 g center dot s(-1). The ablation products were mainly W oxides and complex oxides of W-Ta-O.