Study on the influence of subsonic airflow and laser coupling on aluminum alloy ablation

This study systematically investigated the coupling effect of subsonic tangential airflow and continuous wave laser power on the ablation of 2024 aluminum alloy. The focus was on analyzing the influence of different laser power densities on aluminum alloy ablation at typical flow rates, the effect of airflow presence or absence on ablation, and the regulation of ablation by flow rate. The results show that under the same airflow conditions, power density dominates ablation efficiency; tangential airflow affects the ablation process through cooling and exfoliation effects; at 30 m/s, cooling suppression is dominant, resulting in insufficient exfoliation force; at 50 m/s, the exfoliation effect dominates, leading to the highest efficiency; at 70 m/s, the material removal efficiency decreases due to excessive cooling. Starting from the convective heat-flux and the enthalpy-flux carried away by shear-induced removal, we theoretically compare the cooling and shear-driven stripping effects associated with the airflow velocity, identify the dominant mechanism under different velocities, and thereby validate the rationality of the experimental results. Moreover, comparison between stationary and moving-beam ablation, moving-beam ablation rearranges the hot-zone location and the molten-layer distribution.