Material removal mechanism of superalloy Inconel 718 based on electrochemical abrasive jet processing

This paper proposes a high-efficiency and high-precision processing method for Inconel 718 called electrochemical abrasive jet processing (ECAJP). A mixture of an electrolyte solution and abrasive particles was sprayed from the nozzle and impacted the surface of a material while a direct-current potential was applied. The removal mechanism of ECAJP for Inconel 718 was investigated by comparing and analysing the material removal efficiency and micromorphological features and by performing energy-dispersive X-ray spectroscopy (EDS) analyses of the processing area for different processing methods (including abrasive jet processing (AJP), electrochemical jet processing (ECJP), and ECAJP). The results indicated that under the experimental conditions, there was almost no material removal for AJP. The material removal rate for ECAJP was significantly higher than the sum of those for AJP and ECJP. Electrochemical corrosion was the main form of material removal, and abrasive erosion was auxiliary in ECAJP. The microscale morphologies in the processing area and EDS analyses indicated that the microstructures of Inconel 718 had significant effects on the material removal mechanism of ECAJP. The different electrode potentials between different regions led to anisotropic removal of material in Inconel 718 and significantly affected the surface quality. The surface elements reacted with O and formed passive films. However, the synergistic effect of abrasive erosion and electrochemical corrosion removed the passive films, increased the removal rate, and reduced the anisotropy.