A Sustainable Hybrid Machining Method for Superalloy: Diamond Wire Electrochemical Grinding with Environmentally Benign Electrolyte (D-WECG)

Hastelloy X (HX), a nickel-based superalloy, is essential for aerospace. However, conventional manufacturing methods are unsustainable, energy-intensive, and environmentally polluting. To address these issues, a novel hybrid diamond wire electrochemical grinding with environmentally benign NaHCO3 electrolyte (D-WECG) is proposed. After optimizing NaHCO3 electrolyte parameters through electrochemical testing, characterization and comparative experiments demonstrated that D-WECG is an energy-efficient, low-loss, and recyclable machining process with low levels of pollutants in the solution and negligible heavy-metal ion residues. Simulation and characterization of the passivation film’s physicochemical properties indicate that the uniform passivation film formed by NaHCO3 electrolyte, together with the electrochemical softening effect, enables optimized electrochemical-mechanical coupling, thus reducing mechanical removal energy, mitigating tool wear, and clarifying the mechanism of D-WECG’s enhanced performance. An MRR model was established to capture the coupling of electrochemical and mechanical effects, and key parameters were identified to improve energy efficiency. D-WECG parameters were optimized through response surface methodology, and typical structural components were fabricated to verify the D-WECG’s long-term stability, with analyses of residual stress and surface integrity confirming the superiority of D-WECG’s machining quality. Compared with mechanical grinding, energy consumption and tool wear decreased by 87.3% and 53.7%, respectively, with carbon emissions reduced to 91.8 g/mm3 from 722.2 g/mm3, and the removal energy was 16.7% lower than that of ECM. This study proposes an environmentally friendly, energy-efficient, and high-quality machining method for nickel-based superalloys, demonstrating its potential for green, sustainable manufacturing.