Effect of surface morphology and microstructure on the corrosion behavior of Inconel 718 superalloy prepared by laser additive and subtractive hybrid manufacturing

In the current study, Inconel 718 parts were manufactured utilizing a laser additive and subtractive hybrid manufacturing methods to control surface microstructure and enhance performance. The microstructural analysis and corrosion behavior of Inconel 718 superalloy fabricated using LDED and post-deposition laser hybrid treatment are studied and compared. The result show that the corrosion resistance of LDED Inconel 718 is inferior to that of laser hybrid fabricated alloy. After hybrid production using laser additive and subtractive processes, the precipitated phase is evenly distributed and has shrunk in size and the microstructure is significantly refined. The self-corrosion current density of the sample is considerably reduced from 1.52e⁻³ A/cm² to 3.43e⁻⁵ A/cm² after laser reduction and polishing. Compared to the LDED Inconel 718, there is a significant increase in the capacitive arc and the amplitude of the impedance curve in the middle and lower frequency bands. According to the corrosion test results and theoretical analysis, the corrosion behavior of the laser additive and subtractive hybrid manufacturing Inconel 718 alloy in the salt mixture solution is closely related to the dissolution of the Laves phase and the formation of the passive film.