Microstructure analysis of fusion layer melted CrFeNb on Ni-base superalloy

A coating has been made on K4169 substrate by argon arc cladding technique with the inter-metallic compound(IMC) of CrFeNb. The microstructure and element distribution of the cladding coating were analyzed by scanning electron microscope(SEM) and energy-dispersive spectrum(EDS). The results showed that a fusion layer with a thickness of 64.8μm was formed between the K4169 substrate and CrFeNb. In the fusion layer, the dendritic solidification of cladding CrFeNb stretched into the substrate and cross joined, which formed favorable metallurgical conjunction without the metallurgical defects such as alveolate air holes or cracks. According to the proportion relationship of atomic numbers, two new composite phases of Cr-FeNi-Nb were formed in the fusion layer, and the calculated results showed that they were Cr_(7.16~25.0)-Fe_(6.39~23.4)-Ni_(10.6~56.9)-Nb and Cr_(1.60~3.48)-Fe_(1.44~3.11)-Ni_(2.84~7.20)-Nb, respectively.