同步送粉激光熔注制备WCp&H13钢复合材料层的微观组织和摩擦磨损性能

Microstructure and Wear Resistance of Metal Matrix Composite Layer Fabricated by Simultaneous Powder-delivery Laser Melt Injection

摘要:

以铸造WC（WC/W2C共晶）作为增强颗粒，4Cr5MoSiV1作为熔注层金属基体，采用激光熔注技术在Q235表面制备WCp/4Cr5MoSiV1金属基复合材料层。采用XRD、OM 、SEM和EDS对涂层的物相、宏观形貌和微观组织进行了表征分析，测试了涂层沿深度方向上的显微硬度，室温条件下进行销盘式面接触干滑动摩擦磨损试验，利用SEM对磨损表面进行微观组织分析。研究表明，复合材料层的相组成主要有γ-Fe、WC、M2C、M6C、M23C7、(Fe,W)3C（M=（Fe，Cr，W，Mo）），碳化物在复合材料层中呈现不同的形态。复合材料层的硬度723.74HV0.2，是基材Q235硬度的4.6倍，较传统淬火态4Cr5MoSiV1高出50%。复合材料层的平均摩擦系数为0.283，仅为硬质合金的87.1%、4Cr5MoSiV1的61.1%；相对磨损率43.45，是硬质合金的1.7倍，4Cr5MoSiV1的43倍。

Abstract:

Casting WC particles (WCp) were used as reinforced particle, 4Cr5MoSiV1 steel particles were used as metal matrixs, and Laser Melt Injection (LMI) was employed to produce WCp/4Cr5MoSiV1 metal matrix composite on Q235 steel. Microstructure of MMC layer was analyzed by X-ray diffraction (XRD), Optical microscopy (OM) and scanning electron microscopy (SEM), microhardness was tested along the depth direction of the coatings, pin-on-disk wear test was conducted at room temperature, and morphologies of worn surfaces was analyzed by SEM. Results show that the compound layer mainly comprises γ-Fe, WC, M2C, M6C, M23C7, (Fe,W)3C (M=(Fe, Cr, W, Mo), carbides exhibit different forms in the composite layer. The hardness of the compound layer is 723.74HV0.2, which is 4.6 times of the substrate and 50% higher than traditional hardened 4Cr5MoSiV1 steel. The average friction coefficient of MMC layer is 0.283, which is only 87.1% of the cemented carbide and 61.1% of the 4Cr5MoSiV1 steel. The relative wear rate is 43.45, which is 1.7 times of the cemented carbide and 43 times of the 4Cr5MoSiV1 steel.