Mechanisms of external magnetic field influence on electrical discharge machining of SiCp/Al composites
Tengfei Han, Kan Wang, Jinlai Wang, Guangyang Xin, Yong Liu, Qinhe Zhang
Abstract
• Molecular dynamics simulations show external magnetic fields shift the crater's deepest point, verified by experiments. • The external magnetic field’s effect on plasma channel magnetic field distribution was analyzed mathematically. • Machining mechanism clarified via theory and experiments, accounting for external magnetic field and SiC p /Al composites. Silicon carbide-reinforced aluminum (SiC p /Al) composites are widely used in aerospace and automotive industries due to their exceptional mechanical properties. Electrical discharge machining (EDM) is commonly employed to process these composites, with external magnetic fields enhancing surface quality. However, the mechanisms of magnetic field effects on material removal remain unclear. This study investigates how external magnetic fields influence EDM of SiC p /Al composites through mathematical modeling, simulations, and machining experiments. Analysis of external magnetic field interactions reveals that the field modifies particle trajectories, increases discharge energy, and alters the pinch effect. Finite element simulations show peak electric field strength at Al-SiC junctions, promoting localized electric spark generation and SiC removal. Under the magnetic field, the higher SiC volume fraction magnifies the heat accumulation. Molecular dynamics (MD) simulations demonstrate that the magnetic field shifts crater deepest points, reducing depth while increasing diameter and volume. Single-pulse experiments corroborate these results, with crater volume expanding 34.6 % at 0.2 T. Drilling experiments confirm improved machining efficiency under magnetic fields, achieving higher material removal rate and lower surface roughness. This research elucidates how magnetic fields optimize SiC p /Al machining by redistributing particle energy and modifying plasma dynamics, offering actionable strategies to enhance EDM precision and productivity for high-performance composites.