Microstructure of fusion zone deposited intermetallics CrFeNb on Nickel-base superalloy K4169

High temperature inter-metallic compound CrFeNb coating was deposited on Nickel-base superalloy(K4169) by argon arc cladding process. Scanning electron microscope(SEM), energy-dispersive spectrum(EDS) and X-ray diffraction(XRD) were used to analyze the microstructure and composition distribution of the cladding coating. The results showed that the fusion layer with thickness of 42μm formed between K4169 and high temperature intermetallic compound. There are no metallurgical defects such as pores or cracks in the fusion zone. The metallurgical bonding is realized between the substrate and the CrFeNb coating. Based on the EDS and XRD analysis, it is found that the fusion zone is composed by γ, γ', Fe₂Nb phase and CrFeNb phase, and all these phases are existed in the ways of tiny based-material, white block and chrysanthemum structure. A nested structure is formed between the deposited metal material CrFeNb and based-material K4169 by epitaxial solidification and taking high melting point CrFeNb phase as nucleation.