The effect of tantalum carbide addition on densification of HfC-based composite

: TaC-HfC composites with various contents of tantalum carbide powder (0, 10, 20, 25 and 30 vol.%) were prepared via pressure less method and sintered at 2200, 2300 and 2400 °C. Physical and mechanical properties of the samples including density, hardness, modulus elastic and microstructure were investigated. In this research, it was found that density increases by rising tantalum carbide percentage in hafnium carbide-based composite and increasing sintering temperature, so that relative density changes from 52.8% in zero vol.% TaC composite to 64.55% in 30 vol.% of it at 2200 °C sintering temperature. Also, the hardness of the samples increased as the sintering temperature and tantalum carbide additives increased. The highest value of the hardness obtained as 26 GPa for the HfC-25 vol.% TaC composite sintered at 2400 °C. Microstructure studies showed less porosity and more density by sintering the composite at higher temperature and TaC content.