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利用CO2激光在Q235低碳钢表面激光熔覆制备Ni60合金。分别用扫描电镜、能谱分析、显微硬度计对熔覆层的微观组织、成分分布、显微硬度进行了测定与分析。结果表明,激光熔覆Ni60涂层组织为典型的快速凝固组织。熔覆层底部为垂直于界面生长的胞状结构,中部为树枝状结构且晶粒生长具有单一方向性,顶部也为枝状结构,其晶粒生长呈多向性。枝晶间存在着大量的共晶化合物,黑色区域内含有大量的合金渗碳体等金属间化合物。通过固溶强化、弥散强化、硬质相强化以及细晶强化作用,熔覆层的显微硬度明显高于基材,达到了强化表面的目的。
Preparation of Ni60 Alloy by CO2 Laser Cladding on the Surface of Q235 Low Carbon Steel. The microstructure, composition distribution and microhardness of the cladding layer were measured and analyzed by SEM, EDS and microhardness tester respectively. The results show that laser cladding Ni60 coating is a typical rapid solidification structure. The bottom of the cladding is a cell structure growing perpendicular to the interface. The middle part is a dendritic structure and the grain growth has a single direction. The top is also a dendritic structure, and the grain growth is multidirectional. Dendrites exist between the large number of eutectic compounds, black region contains a lot of alloy cementite and other intermetallic compounds. By solid solution strengthening, dispersion strengthening, strengthening of the hard phase and fine grain strengthening, the microhardness of the cladding layer is significantly higher than the substrate, to achieve the purpose of strengthening the surface.