Surface improvement of laser solid forming Inconel 718 by electrochemical machining

Surface improvement of laser solid forming Inconel 718 by electrochemical machining was investigated. Microstructure observation shows that there exists a fiber texture and the «001» direction is parallel to the build direction. Furthermore, the alloying elements of Nb, Mo, and Ti are rich in interdendritic regions, and γ/Laves eutectic phase and γ/carbides eutectic phase are located in the interdendritic regions. Besides, the surface morphologies are wavy due to the overlapping of the scanning tracks and the stacking effect between deposited layers. Electrochemical results show that the top surface requires less time to obtain a smooth surface profile than the side surface due to their original surface profiles difference and the less volume of the bulges on the top surface. The numerical simulation indicates that the uneven surface profiles become smooth owing to the fact that the surface peaks dissolve faster than the surface depressions. These results provide an insight into improving the surface quality of the as-deposited Inconel 718.