球墨鑄鐵表面激光熔覆TiC/Co基合金組織和性能研究球墨鑄鐵表面激光熔覆TiC/Co基合金組織和性能研究Microstructure and properties of TiC/Co based alloy by laser cladding on the surface of nodular graphite cast iron 為了研究TiC增強相對球墨鑄鐵表面激光熔覆鈷基合金性能影響，采用6kWCO2激光器進行激光熔覆，通過掃描電鏡（SEM）、EDS、XRD、MHV2000數(shù)顯顯微硬度計，分析了熔覆層的顯微組織、成分、物相、熔覆層的硬度變化規(guī)律。結(jié)果表明，球墨鑄鐵基體與熔覆層能形成良好的冶金結(jié)合，熔覆層由表層的樹枝晶和內(nèi)部的胞狀晶組成，從熔體中原位析出初晶TiC，且初晶TiC的量從熔覆層內(nèi)部到表層逐漸增加，而未熔的TiC顆粒在晶間均勻分布著，熔覆層主要由γ-Co、TiC、NiTi、CoCx和少量的Cr7C3、SiC等相組成，熔覆層的最高硬度是1278.8HV，提高到球墨鑄鐵基體的5倍以上。 In order to study the effect of TiC reinforced phase on the properties of Laser Cladding Co-based alloy on the surface of nodular graphite cast iron, laser cladding is done using 6kW CO2 laser. The microstructure, composition, phase, hardness of the laser cladding layer are analyzed by scanning electron microscopy (SEM), EDS, XRD and MHV2000 digital micro hardness tester. The results show that, the cladding layer can be integrated metallurgically with the nodular graphite cast iron matrix. The cladding layer consists of a surface layer of dendritic crystals and an internal cellular crystal. The primary phase of TiC from the melt is precipitated. The amount of primary TiC is gradually increased from the inner layer to the surface layer. Meanwhile, the dissolved TiC is uniformly distributed in the middle of dendrites. The laser cladding layer is mainly composed of γ-Co, TiC, NiTi, CoCx and a small amount of Cr7C3 and SiC. The maximum hardness value of the cladding layer is 1278.8HV, up to5 times more than the hardness of the substrate of nodular graphite cast iron.
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