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采用预涂粉末激光熔覆技术,在45~#钢表面制备出原位生成TiC-ZrC颗粒增强的镍基复合涂层。使用扫描电镜(SEM),EDS能谱和X射线衍射(XRD)对熔覆层的显微组织和物相构成进行了分析,并对熔覆层进行了硬度、摩擦性能测试。结果表明,在适当的工艺条件下,原位生成TiC-ZrC颗粒增强镍基复合涂层形貌良好,涂层与基材呈冶金结合。熔覆层底部组织为定向生长的γ(NiFe)树枝晶,熔覆层中上部组织为先共晶析出的TiC-ZrC颗粒相和Cr_3C_2条状相均匀分布于γ(NiFe)树枝晶基体中。熔覆层具有高的硬度(平均硬度HV_(0.3)1300)和良好的耐磨性,与纯Ni60熔覆层相比,其磨损失重仅为纯Ni60熔覆层的1/4。熔覆层硬度和耐磨性的提高归因于大量TiC-ZrC复合颗粒的形成及其在涂层中的均匀弥散分布。
Pre-coated powder laser cladding technology was used to prepare in-situ TiC-ZrC particles reinforced Ni-based composite coatings on 45 ~ # steel. The microstructure and phase composition of the cladding layer were analyzed by scanning electron microscopy (SEM), EDS and X-ray diffraction (XRD). The hardness and friction properties of the cladding layer were tested. The results show that the morphology of in-situ TiC-ZrC particles reinforced nickel-based composite coating is good and the coating is metallurgically bonded with the substrate under appropriate process conditions. The microstructure of the cladding layer is oriented growth of γ (NiFe) dendrites. The upper structure of the cladding layer is the first eutectic TiC-ZrC particles and the Cr_3C_2 strip-like phase uniformly distributed in the γ (NiFe) dendrite matrix. The cladding layer has high hardness (average hardness HV_ (0.3) 1300) and good wear resistance. Compared with the pure Ni60 cladding layer, the wear loss is only 1/4 of the pure Ni60 cladding layer. The increase in hardness and wear resistance of the cladding layer is attributed to the formation of bulk TiC-ZrC composite particles and their uniform dispersion distribution in the coating.