抄録
The micro-grained WC-(6-13)mass%Co alloys containing VC up to 5mass% in binder were sintered in vacuum under different conditions. Mechanical properties of the alloys such as hardness(HV) and transverse-rupture strength (σm) were studied as a function of carbide grain size(d ?? =0.25-1.3μm) or mean free path of binder(λ=0.02-0.13μm), and Co content.
The HV of micro-grained alloys was suggested to increase towards a value between 1800 and 1900 with decreasing d ?? (λ), in no relation to the Co content. The alloys were found to show a excellent value of σm that is, 3.0-4.0GPa (according to the Japanese industrial standard), because the defect size acting as the fracture source became smaller in the micro-grained alloys comparing with that of the usual alloys having coarser carbide grain size. It was noted that fractured structure developed just under the Vickers hardness indentation in each alloy.
