激光熔覆原位生成NbC增强Ni基合金涂层磨损性能研究

Investigation of abrasion behavior of in-situ generated NbC reinforced Ni-based alloy coatings by laser cladding

关键词:  金属陶瓷  激光熔覆  原位生成  NbC颗粒增强  磨粒磨损

Key words:  metal ceramic  laser cladding  in-situ generation  NbC particle reinforced  abrasion

摘要:

为揭示NbC增强Ni基合金涂层的磨损性能,利用激光熔覆技术原位生成了不同Nb/C比例的NbC增强Ni基合金涂层。使用扫描电子显微镜(SEM)、能谱仪(EDS)和X射线衍射仪(XRD)分析了涂层的相组成与原位生成NbC颗粒的显微形貌与分布,检测了样品的显微硬度与耐磨性。结果表明:原位生成的NbC颗粒在涂层中分布均匀,体积占比最高达49.264%；随着Nb含量的提高,NbC形态从十字形变为球形和矩形；涂层中弥散强化与固溶强化是主要的强化机制；随着Nb/C比例增大,涂层的硬度提高；在湿砂磨粒磨损条件下,样品的耐磨性与硬度呈正相关。综合来看,Nb质量分数45%、Cr₃C₂质量分数35%时制得的涂层具有最高的NbC含量,而Nb质量分数50%、Cr₃C₂质量分数30%的涂层具有最高的硬度与耐磨性。

Abstract:

To reveal the abrasion behavior of NbC reinforced Ni-based alloy coatings, NbC-reinforced Ni-based alloy coatings with different Nb/C ratios were prepared by laser cladding technology. The phase composition, microstructure, and distribution of in-situ generated NbC particles in the coatings were analyzed using scanning electron microscope (SEM), energy dispersive spectrometer (EDS) and X-ray diffraction (XRD). The microhardness and abrasion resistance of the coatings were analyzed. The results show that the in-situ generated NbC particles are uniformly distributed in the coatings with a volume proportion up to 49.264%. As the Nb content increased, the morphology of NbC changed from cross-shaped to spherical and rectangular. Dispersion strengthening and solid solution strengthening are the main strengthening mechanisms in the coatings. The hardness of coatings increased in accordance with the growth of the Nb/C ratio. The abrasion resistance of coatings under wet sand abrasion conditions is positively correlated with hardness. Overall, the coating with 45 wt.% Nb and 35 wt.% Cr₃C₂ have the highest NbC content, while the coatings with 50 wt.% Nb and 30 wt.% Cr₃C₂ exhibits the highest hardness and wear resistance.