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

Abstract

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.