Performance assessment of nano-SiC-mixed electro discharge machining of Inconel 825

Inconel 825 is extensively utilized in corrosive environments; however, its low heat conductivity, work hardening and high-temperature strength make it difficult to machine. Electro discharge machining (EDM) is an advanced machining technique commonly utilized to machine Inconel 825 but its application is limited due to its high surface roughness and poor machining rate. Therefore, to enhance the machining capability of EDM, the present work uses deionized water with and without mixing nano-silicon carbide (SiC) particle as a dielectric medium during EDM of Inconel 825 and investigates the influence of powder concentration and current on key performance parameters such as surface roughness (Ra), tool wear rate (TWR), and material removal rate (MRR). In case of nano-SiC-mixed EDM, experiments are conducted by varying the current from 6A to 9A and the particle concentration from 0.5 g/L to 1.5 g/L. A comparative analysis of nano-SiC-mixed EDM with conventional EDM reveals that the nano-SiC-mixed dielectric medium improves MRR, TWR, and Ra by 40.42%, 7.60%, and 6.92%, respectively, on average. It has also been observed that adding SiC to the dielectric medium can improve MRR, TWR, and Ra up to 46.88%, 16.77%, and 8.96%, respectively. The minimum improvement of MRR, TWR, and Ra using the nano-SiC-mixed dielectric medium is 25.01%, 2.51%, and 5.45%, respectively. Further, the FESEM micrographs reveal fewer surface imperfections at particle concentration of 1 g/L while energy-dispersive X-ray spectroscopy analysis indicated minimal electrode material migration at this concentration.