Temperature- and electrolyte-dependent material removal mechanisms in synchronous laser-electrochemical drilling of SiCp/Al composites

Deep micro-hole drilling in SiC p /Al composites remains challenging in conventional processes because hard SiC particles and heterogeneous Al-SiC interfaces complicate material removal, resulting in severe tool wear, low machining efficiency, and poor surface integrity. In this study, synchronous laser-assisted electrochemical machining (LECM), combining central laser irradiation with peripheral electrochemical dissolution, was developed for efficient and high-quality drilling of SiC p /Al composites. The effects of electrolyte composition, laser power, SiC volume fraction, voltage, and electrode feed rate on the material removal rate, surface roughness, and precision were investigated. The material removal mechanisms were analyzed through multiphysics simulation, in-situ temperature measurement, electrochemical testing, and surface characterization. At a laser power of 7 W, the maximum stable feed rates reached 5.1 mm/min and 1.9 mm/min for the 15 vol% and 30 vol% SiCp/Al composites, respectively, compared with 2.0 and 1.1 mm/min for conventional ECM. Electrochemical testing revealed that below 50 °C, the passive film’s effects strengthened with rising electrolyte temperature and laser power, improving surface quality; above 50 °C, passive-film breakdown at lower potential combined with accelerated dissolution rate enhanced surface quality. NaNO 3 electrolyte provided more stable passivation-controlled dissolution and better sidewall quality than NaCl. Finally, 10-mm-deep micro-holes were fabricated without recast layer, demonstrating the feasibility of LECM for deep micro-hole drilling in SiC p /Al composites.