Factors affecting the hardening of WC-(Ni_1-xM_x) (M = Co, Cu, W) cemented carbides with different solute elements in Ni alloys

In this study, WC-Ni cemented carbide, which has mechanical properties inferior to those of WC-Co cemented carbide, was hardened using Ni alloys. Changes in the solid-solution strengthening factors (shear modulus, lattice strain, and solute concentration) with the type and content of solute elements were investigated in Ni alloys, and the requirements of the solute elements for hardening WC-Ni were studied. When Co was used as a solute element, the Ni alloys became stiffer, making the shear modulus the most dominant factor in the hardening of WC-Ni. However, when Cu and W are used as solute elements, WC-Ni hardening occurs mainly by lattice strain. The evaluation of the Ni alloy properties confirmed that the lattice strain was more effective than the shear modulus, resulting in WC-Ni hardness properties in the order WC-(Ni_1-xCo_x) < WC-(Ni_1-xCu_x) < WC-(Ni_1-xW_x). Finally, it was found that the hardness properties of WC-(Ni_1-xCo_x), WC-(Ni_1-xCu_x), and WC-(Ni_1-xW_x) were in the range of 15.2–15.6, 14.6–18.0, and 16.6–19.7 GPa, respectively, which are higher than the previously reported hardness values of WC-Ni/Co cemented carbides with metallic phases of 10 wt%. In addition, it was confirmed that the hardness and fracture toughness of WC-Ni can be tuned by changing the type and proportion of solute elements in the Ni alloy. The Ni-alloyed WC-Ni presented in this study not only exhibits high hardness but also enables property control through alloy element adjustment, which is expected to contribute to the production of tools for high-speed machining and customized tools.