Abstract:Aircraft laser paint removal might cause potential damage to the 2024 aluminum alloy skin. It was necessary to explore the effect of laser parameter changes on the surface of the matrix material, in which the pulse width had an important impact on the laser-material interaction and material damage characteristics. In this paper, the temperature rise characteristics of the aluminum alloy surface exposed to laser with different pulse width were simulated and analyzed by COMSOL Multiphysics software, and the ISO 11254 1-on-1 laser damage threshold test method was used to reveal the influence of pulse width on aluminum alloy damage threshold. Furthermore, the micro-morphology, diameter and depth of ablation pits were further analyzed under different pulse widths. The results show that the peak temperature of aluminum alloy surface decreases with the increase of pulse width. When the pulse width increases from 150 ns to 240 and 330 ns, the damage threshold of aluminum alloy increases from 9.96 J/cm2 to 11.24 and 12.66 J/cm2, respectively. The laser energy density reaches the damage threshold, the 3 μm thick oxide film is completely damaged, which destroys the surface integrity of the aluminum alloy. The diameter and depth of the ablation pits increase with the increase of the pulse width, and the depth is more affected. This research can provide a reference for the selection of pulse width for the interaction between laser and materials.