Microstructural characterization of laser welding repair of directionally solidified GTD-111 nickel-based superalloy

Wire-based laser metal deposition (WBLMD) is one of the most promising methods for the build-up and repair of the damaged nickel-based superalloys components used in the hot-section of gas turbine engines, in order to extend their lifetime and improve the reliability. In the current study, welding repair of a directionally solidified nickel-based superalloy with a solid solution nickel-based superalloy filler metal, IN625, was investigated. After parameters optimization, microstructural evaluations were carried out by optical and scanning electron microscope. Based on the microstructural evaluation, the built-up microstructure contains of the cellular and dendritic regions, while the interface of base metal and weld metal governs an epitaxial growth regime. The obtained results showed that porosity and microcracks have not been observed, after parameter optimizations.