Synthesis and properties of (Hf1-xTax)C solid solution carbides

Thermodynamically stable (Hf1-xTax)C (x = 0.1-0.3) compositions were selected by First Principle Calculation and synthesized in nanopowders via high-energy ball milling and carbothermal reduction of commercial oxides at 1450 °C. The formation of a solid solution during powder synthesis was investigated. The solid solution carbide powders were sintered at 1900 °C by spark plasma sintering without a sintering aid. As a result, the (Hf1-xTax)C solid solution carbides exhibited high densities, excellent hardness and fracture toughness (ρ: 98.7-100.0%, HVN: 19.69-19.98 GPa, KIC: 5.09-5.15 MPa m1/2) compared with previously reported HfC and HfC-TaC solid solution carbides.