Effect of laser cleaning the anodized surface of 5083 aluminum alloy on weld quality

In this paper, the nanosecond pulse laser was used to clean the anodic oxide film on the surface of 5083 aluminum alloy. The effect of different laser travel speeds on the surface roughness and microhardness of cleaned specimens is studied. The effect of different pretreatment methods on welding performance has also been further explored. The results show that the surface roughness of aluminum alloy after laser cleaning shows a trend of first increasing, then decreasing, and then increasing with the increase of laser travel speed. When the laser travels at a speed of 6.5 mm/s, the surface roughness is relatively lowest, about Ra = 0.381 μm. Appropriate laser cleaning parameters can effectively remove the anodic oxide film on the surface of 5083 aluminum alloy. After laser cleaning, the surface microhardness of the specimen has little change with the increase of laser speed, but it shows a trend of first increasing, then decreasing and finally increasing. Compared with untreated and mechanical polishing, the fish scale pattern on the surface of the weld seam cleaned by laser before welding is uniform and consistent, and there are no defects such as pores. Moreover, the tensile performance has also been improved to a certain extent. There are differences in the fracture mechanisms at the fracture surface under different pretreatment methods. The fracture mechanisms at the fracture surface after untreated, mechanical polishing, and laser cleaning treatments are brittle fracture, ductile brittle mixed fracture, and ductile fracture, respectively.