机械合金化转速对CNTs-SiC/Ni激光熔覆微观结构的影响

Effect of rotation speed in mechanical alloying on microstructure of laser cladding CNTs-SiC/Ni

以机械合金化混合CNTs-SiC/Ni粉末为原料,采用激光熔覆法制备CNTs-SiC/Ni复合涂层,利用扫描电子显微镜电镜(SEM)、能谱仪(EDS)以及金相显微镜(OM)分析碳纳米管的分散性以及熔覆层微观结构,研究转速对复合粉末中碳纳米管的分散性和熔覆层微观结构的影响。结果表明:随着机械合金化转速的提高,镍球表面的包裹层越厚实,碳纳米管分散越均匀,当转速超过350 r/min时混合粉末被击碎,碳纳米管结构被破坏;随着转速的提高,熔覆层等轴晶和小枝晶混合区域面积越大。

The mixed CNTs-SiC/Ni powder by mechanical alloying was used as raw material, and CNTs-SiC/Ni composite coatings were prepared by laser cladding method. The dispersion of carbon nanotubes and the microstructure of cladding layer were analyzed by using scanning electronic microscope （SEM）, energy spectrometer （EDS） and optical microscope （OM）. The effeets of rotation speed on the dispersion of carbon nanotubes and the microstructure of cladding were studied. The results show that with the increase of the rotation speed, the thicker the coating of the nickel sphere, the more uniform the dispersion of the carbon nanotubes. When the rotation speed exceeds 350 r/min, the mixed powder is crushed and the carbon nanotube structure is destroyed. The mixing area of the equiaxed crystal and dendritic crystal in the cladding layer becomes larger with the increase of rotation speed.