Perforation effect of CW laser irradiation on aluminum alloy under subsonic flow

The perforation effect of laser irradiated target is different under different airflow velocity. The perforation effect of 7075 aluminum alloy irradiated by 1070 nm CW laser under subsonic airflow(0-0.7 Ma) was experimentally studied. The temperature history, perforation time, perforation aperture and surface morphology of the center point of the aluminum alloy were analyzed. The results show that under the same airflow velocity, with the increase of the incident laser power density, the temperature rise rate of the aluminum alloy surface increases and the equilibrium temperature of the final melting layer increases. The perforation time of aluminum alloy decreases exponentially; the increase rate of pore size decreases exponentially. At the same laser power density, with the increase of airflow velocity, the perforation time of aluminum alloy increases first and then decreases to a stable and then increases. Both the removal rate of melt and the cooling effect of airflow lead to the longest perforation time near 0.1 Ma and the shortest perforation time near 0.3 Ma. The perforation time of 0.6 Ma is roughly equal to that of 0 Ma about 5.5 s. With the increase of airflow velocity, the cooling effect increases, and there is no perforation in the aluminum alloy after 0.7 Ma. Convection cooling leads to rapid condensation of the melt, and the removed melt concentrates in the downstream area of the airflow.