铝青铜表面激光熔覆镍基涂层的组织与磨损性能

Microstructure and Wear Resistance of Laser Cladding Nickel-Based Coating on Albronze

为了改善铜合金表面的耐磨性能,利用超音速火焰喷涂和激光重熔技术在铝青铜上制备了镍基涂层。分析了激光熔覆层的微观组织,测试了其显微硬度及磨损性能。结果表明:熔覆层组织致密、无裂纹,与铝青铜形成了良好的冶金结合;从熔覆层表层到基体热影响区,组织呈现出由细小的柱状晶→胞状晶、树枝晶→平面晶过渡;激光熔覆层磨损量约为铝青铜的1/4,熔覆层耐磨能力的增强归因于熔覆层与铝青铜间良好的冶金结合及基体与涂层元素固溶强化和碳化物等析出相的强化作用。

Ni-based coating was prepared on the surface of albronze by high velocity oxy-fuel spraying and laser cladding so as to improve the wear resistance.The microstructure of the laser cladding coating was analyzed,and its microhardness and wear resistance were evaluated.It was found that the laser cladding coating was compact and free of cracks,well combining with the albronze substrate via metallurgical bonding.From the surface of the cladding layer to the heat-affected zone of the substrate,the microstructure had a transformation from columnar crystal to cellular crystal,dendritic crystal and plane crystal.Besides,the wear mass loss of the laser cladding coating was only about 1/4 of that of the substrate,showing good wear resistance.This may be mainly attributed to the strong metallurgical bonding between the laser cladding coating and substrate as well as solution strengthening effect and strengthening effect of precipitation phases like carbides.