The Effect of Cr₃C₂ and TaC Additives on Microstructure, Hardness and Fracture Toughness of WC-6Co Tool Material Fabricated by Spark Plasma Sintering

Spark plasma sintering has been used to successfully produce WC-6Co-xCr₃C₂, WC-6Co-xTaC (x = 0.2, 0.6, 1.0) and WC-6Co-xCr₃C₂-xTaC (x = 0.1, 0.3, 0.5) cemented carbides. The spark plasma sintered compacts were investigated by scanning electron microscopy, hardness tests and fracture toughness tests. The results were compared to an additives-free WC-6Co cemented carbide consolidated under the same process parameters and commercial ISO K10 inserts. By using Cr₃C₂ and TaC additives, it is possible to improve the hardness and fracture toughness of WC-Co cemented carbides. The best combination of hardness (1936 ± 15 HV₃₀) and fracture toughness (10.38 ± 0.46 MPa∙m^1/2) was obtained by the WC-6Co-1Cr₃C₂.

Keywords:
Spark plasma sintering; Cemented carbide; Chromium carbide; Tantalum carbide; Mechanical properties