Magnetic field-assisted ECDM of SiCp/Al composites: process optimization and validation

Silicon carbide-reinforced aluminum matrix composites (SiCp/Al) are widely applied in aerospace and electronics for their excellent mechanical performance. However, conventional electrical discharge machining (EDM) of SiCp/Al suffers from severe electrode wear, poor surface integrity, and recast layer formation. To overcome these challenges, this study proposes magnetic field-assisted electrochemical discharge machining (MF-ECDM), replacing the MF-EDM dielectric fluid with a low-conductivity NaNO3 solution. A single-factor experiment investigated how electrolyte conductivity influences machining behavior. Results revealed that increasing conductivity decreases material removal rate (MRR) and relative tool wear ratio (RTWR), but enlarges overcut (OC). Grey relational analysis with orthogonal experiments identified optimal parameters, achieving MRR of 16.75 mm3/min, and OC of 110 µm. Furthermore, a dual sacrificial layer technique was developed to improve small-hole machining by enhancing electrolyte-wall contact, reducing stray corrosion, and compensating for electrode wear. Under optimized conditions, MF-ECDM reduced tool wear by 25–27.71% and improved surface quality compared with EDM and MF-EDM, demonstrating potential for high-quality machining of ceramic-reinforced composites.