超细硬质合金WC晶粒大小对其摩擦磨损性能的影响

Effect of WC Grain Size of Ultrafine WC-Co Cemented Carbide on its Friction and Wear Properties

为了研究超细硬质合金WC晶粒大小对其摩擦磨损性能的影响,采用不同烧结工艺制得WC平均晶粒度分别为0.25、0.35、0.50μm的三种合金。通过密度天平、硬度计、摩擦磨损试验仪、三维轮廓扫描仪和扫描电镜等对合金进行表征分析。结果表明,合金的相对密度和硬度随着WC晶粒尺寸的增大而呈降低的趋势。WC平均晶粒度为0.25μm的合金,硬度高,往复摩擦过程能有效抵抗对磨球的作用,磨痕深度较浅,显示出较好的耐磨性能。当WC平均晶粒尺寸增加到0.35μm时,对磨球的侵入深度明显增加,合金的耐磨性能降低。继续增加WC平均晶粒尺寸到0.50μm,合金的硬度持续降低,磨损形貌中出现WC颗粒的破碎相,对磨球的侵入深度进一步增加,耐磨性能最差。

In order to study the effect of WC grain size of ultrafine cemented carbide on its friction and wear properties, ultrafine cemented carbides with the average WC grain sizes of 0.25 μm, 0.35 μm and 0.50 μm were prepared by different sintering processes.The alloys were characterized and analyzed by density ba-lance, hardness tester, friction and wear tester, 3 D contour scanner and scanning electron microscope.The results show that the relative density and hardness of the alloys decrease with the increase of WC grain size.The alloy with an average WC grain size of 0.25 μm has high hardness, can effectively resist the effect of grinding balls during reciprocating friction, and has a shallow depth of wear scars, showing good wear resistance.When the average WC grain size increases to 0.35 μm, the penetration depth of the grinding ball significantly increases, and the wear resistance of the alloy decreases.Continuing to increase the average WC grain size to 0.50 μm, the hardness of the alloy continues to decrease, some broken WC particles appear in the wear morphology, the penetration depth of the grinding ball further increases, and the wear resistance is the worst.