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采用激光熔覆法将Ni60熔覆层沉积在中碳钢基体上,采用能谱、电子背散射衍射技术和扫描电镜分析了稀释率对化学成分、相组成、微观结构演化的影响,并且还测量了激光熔覆后熔覆层的显微硬度分布。结果表明,激光熔覆的过程参数对稀释率有很大的影响,稀释率随激光功率、扫描速度的增加而增加,随送粉量的增大而减小。稀释率的变化能引起熔覆层中析出相类型和形态的改变,过高的稀释率会抑制硼化铬、碳化铬的析出,并减少共晶组织含量。由于硼化铬、碳化铬、Ni-B-Si共晶的减少和熔覆层中铁含量的增加,Ni60熔覆层的硬度从1 000HV0.5下降到600HV0.5。
Ni60 cladding layer was deposited on medium carbon steel by laser cladding. The influence of dilution rate on the chemical composition, phase composition and microstructure evolution was analyzed by energy dispersive spectroscopy, electron backscatter diffraction and scanning electron microscopy. After the laser cladding cladding layer microhardness distribution. The results show that the laser cladding process parameters have a great influence on the dilution rate. The dilution rate increases with the increase of laser power and scanning speed, but decreases with the increase of powder feeding rate. Changes in the dilution rate can cause changes in the type and morphology of precipitates in the cladding layer. Excessively high dilution rates inhibit the precipitation of chromium boride and chromium carbides and reduce the eutectic content. The hardness of Ni60 coating decreased from 1000HV0.5 to 600HV0.5 due to the reduction of chromium boride, chromium carbide, reduction of Ni-B-Si eutectic and the increase of iron content in the cladding.