The micro-grained WC-10mass%Ni medium carbon alloys having additional VC up to 10mass% in binder were sintered in vacuum at 1450-1500°C, using starting WC powder with particle size of 0.7 and 1.4μm. The mechanical properties of the alloys such as hardness(HV) and transverse-rupture strength(σm) were mainly studied as a function of carbide grain size (d_WC) in the range from 1.5 to 0.4μm. The results obtained were compared with those of micro-grained WC-10mass%Co alloys previously reported by the present authors.
It was found that the RV and σm of WC-Ni alloy increased with decreasing d_WC towards the values of micro-grained WC-Co alloy. It was also found that the above values became almost the same as those of WC-Co alloy, when d_WC decreased to the values less than 0.5-0.6μm. The phenomena were in detail discussed from a viewpoint of characteristics different between Ni and Co binder metals.