Fig. 1. Laser etched pattern

Fig. 2. SEM images of aluminum alloy surface by laser etching under different laser power densities. (a) Power density is 371.55 J/cm²; (b) power density is 583.86 J/cm²; (c) power density is 796.17 J/cm²

Fig. 3. Three-dimensional contour images of aluminum alloy surface by laser etching under different laser power densities. (a) Power density is 371.55 J/cm² (Ra=7.503 μm); (b) power density is 583.86 J/cm² (Ra=8.167 μm); (c) power density is 796.17 J/cm² (Ra=8.793 μm)

Fig. 4. SEM images of aluminum alloy surface by laser etching before and after heat treatment. (a) Before heat treatment; (b) after heat treatment

Fig. 5. Water contact angle of aluminum alloy surface by laser etching. (a) Before heat treatment; (b) after heat treatment

Fig. 6. Water droplet contact process before heat treatment

Fig. 7. Water droplet contact process after heat treatment

Fig. 8. XPS images of aluminum alloy surface by laser etching. (a) Before heat treatment; (b) after heat treatment

Fig. 9. XRD image of aluminum alloy surface by laser etching before and after heat treatment

Fig. 10. Infrared spectra of aluminum alloy surface by laser etching before and after heat treatment

Fig. 11. Peak split chart of the XPS C 1s peak. (a) Before heat treatment; (b) after heat treatment

Fig. 12. Changes of various groups on the aluminum alloy surface by laser etching before and after heat treatment