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利用DL-T5000型二氧化碳激光器在QT-500球墨铸铁表面熔覆镍基合金,分析了激光熔覆层的显微组织,测试了其显微硬度及磨损性能。结果表明:所制得熔覆层组织致密、无裂纹,与基体形成了良好的冶金结合。从熔覆层表面到基体热影响区,组织依次为大量的树枝晶、等轴晶、树枝晶。熔覆层的硬度较基体提高了5倍,熔覆层的总磨损率大约为基体的1/6。熔覆层耐磨性能增强的主要原因是镍基合金与涂层元素镍、铬等固溶强化和碳化物等析出相的强化作用。
The Ni-based alloy was deposited on the surface of QT-500 ductile iron by DL-T5000 carbon dioxide laser. The microstructure of the laser cladding layer was analyzed and its microhardness and wear resistance were tested. The results show that the prepared cladding layer has compact structure and no cracks, and forms a good metallurgical bond with the substrate. From the cladding surface to the substrate heat affected zone, the organization followed by a large number of dendrites, equiaxed, dendrites. The hardness of the cladding is increased by 5 times that of the matrix, and the total wear rate of the cladding is about 1/6 of that of the matrix. The main reason for the increase of the wear resistance of the cladding layer is the strengthening effect of the Ni-based alloy and the coating elements of nickel, chromium and other precipitation strengthening phases and carbide precipitation phases.