Nd: YAG laser ablation of aluminum alloy 6061 before and after silicon dioxide coating

•3D Model was used to predict the laser ablation of AA 6061 before and after SiO2 film.•Laser was utilized to redistribute to smooth the material pits and improve its performance.•The protective way of SiO2 film reflected in the ablation depths and irradiation times. In this work, the process of laser ablation of aluminum alloy 6061 (AA 6061) before and after silicon dioxide (SiO2) coating was studied both experimentally and by numerical simulation. Four different laser fluences (0.5 J/cm2, 1 J/cm2, 1.5 J/cm2 and 2 J/cm2) were applied to investigate laser ablation of AA 6061 before and after coated by SiO2 film. It was founded that the thermal diffusion and ablation depth of AA 6061 had been directly influenced by both laser fluence and SiO2 coating. At relatively low laser fluence (0.5 J/cm2), ablation deformation and damage of AA 6061 were not observed. While the laser fluence reached to 1 J/cm2, vaporization took place in AA 6061. With increased laser fluence, the ablation range and depth expanded. The vaporization of SiO2 films happened in the first laser fluence, however, the area of the zone affected were much less than AA 6061, that demonstrates the SiO2 film has a positive effect on AA 6061. A 3-dimensional computational model was used to compute the temperature variation in a solid material over time. The results of the model (depth to width ratio versus laser ablation) exhibited well with the experimental results in some ways.