Jet-guided laser electrochemical machining of 2024 aluminum alloy: Material removal and stray corrosion suppression mechanism

Conventional laser-electrochemical hybrid machining is limited by inefficient laser-electrolyte energy coupling, laser defocusing, and complex tool electrodes. To address these limitations, jet-guided laser electrochemical machining (J-LECM) is proposed, in which the electrolyte jet serves simultaneously as an optical waveguide for laser transmission and as a conductive medium for localized electrochemical dissolution. The effects of peak power density (PPD) on groove geometry, surface quality, stray corrosion, jet stability, and material removal behavior of 2024 aluminum alloy were systematically investigated. Compared with the JECM baseline under the same insulating-nozzle configuration, J-LECM at a PPD of 3.40 × 10 5 W/cm 2 reduced the line edge roughness by 51.8%, decreased the pitting corrosion area ratio and maximum pit size by 88.1% and 69.4%, respectively, and increased the material removal rate by 69.1%. The bottom surface roughness remained acceptable at Ra 2.50 μm. High-speed imaging shows that laser irradiation reduces radial spreading and boundary fluctuation of the electrolyte jet. This stabilizes the contact region between the jet and workpiece and suppresses stray corrosion. Surface characterization and thermal simulation further show a staged material-removal behavior. The dominant mechanism evolves from pure electrochemical dissolution to laser-enhanced electrochemical dissolution, and finally to synergistic laser-electrochemical removal with localized thermal effects. These results clarify the coupled jet-guiding, thermal, and electrochemical mechanisms in J-LECM and demonstrate its potential for high-quality micromachining of aluminum alloy components.