Ti(C,N)粒子を添加した超微粒バインダレス超硬合金の組織と機械的特性

抄録

Ultrafine-grained binderless cemented carbides using 0.4 µm WC particles were prepared by adding Cr₃C₂, VC, TaC, βt and various sizes of Ti(C,N) particles. SEM observations of the polished and fractured surfaces revealed that the WC grains became finer after the addition of the carbides or carbonitrides. In the Ti(C,N)-added binderless cemented carbides, the WC grains became finer with decreasing Ti(C,N) particle size and increasing Ti(C,N) content. The grain size of WC in the binderless cemented carbide containing 0.1 μm Ti(C,N) was comparable to that of the Cr₃C₂-containing binderless cemented carbide, although not as fine as that of the VC-containing binderless cemented carbide. The binderless cemented carbides containing fine Ti(C,N) grains were harder and had higher strengths than the other carbides. The combined addition of fine Ti(C,N) and Cr₃C₂ resulted in more homogeneous WC grains. These results indicate that the grain growth inhibition of binderless cemented carbides varies depending on the type and grain size of the added carbonitrides. These findings will contribute to the future development of binderless cemented carbides.