Microstructure and mechanical properties of WC-Co, WC-Co-Cr3C2 and WC-Co-TaC cermets fabricated by spark plasma sintering

Spark plasma sintering was successfully used to produce WC-Co cermets with the addition of Cr3C2 and TaC grain growth inhibitors. The spark plasma sintered compacts were investigated by scanning electron microscopy, X-ray diffraction analysis, density measurements, hardness tests, fracture toughness tests and elastic modulus tests. The results were compared with an inhibitor-free WC-Co cermet consolidated under the same process parameters. By using Cr3C2 and TaC additives, it is possible to improve the hardness and fracture toughness of WC-Co cermets, but Cr3C2 has better grain growth inhibition property than that of TaC. The best combination of hardness (HV30 (2105±38)) and fracture toughness ((8.3±0.2) MPa·m1/2) was obtained by the WC-5Co-2Cr3C2 cermet.