Comparative study of WC-based hard alloys fabrication via spark plasma sintering using Co, Fe, Ni, Cr, and Ti binders

The paper presents a method of fabrication and a comparison of the characteristics of obtained cemented carbide samples based on tungsten carbide with 10% metal binder. They were synthesized by spark plasma sintering (SPS) at different sintering temperatures: Co (1200 °C), Fe and Ni (1150 °C), Cr (1500 °C), and Ti (1400 °C). During the SPS-consolidation process, investigations of the dilatometric characteristics of samples of starting powders of identical granulometric composition obtained by mixing/grinding resulting in the fractional composition in the particle size range up to 10 μm are presented. The mechanism of phase formation and microstructure of the obtained materials is investigated by XRD, SEM, and EDS. The possibility of synthesizing hard alloys WC – 10%Ti and WC – 10% Cr by the mechanism of reaction SPS synthesis with a reduction in the synthesis time in comparison with traditional sintering methods has been demonstrated. Analyses have shown that during sintering of alloys containing Ti and Cr the volume content of WC decreases to 47% because of dissolution and interaction, while in alloys containing Co, Ni, and Fe, the volume content of WC remains unchanged (85–86%). This led to a dramatic change in hardness, fracture toughness, and strength when replacing Co, Ni, or Fe with Ti or Cr.