Fig. 1. Schematic of laser surface oxidation pretreatment of aluminum alloy

Fig. 2. Schematic of laser direct jointing of aluminum alloy and PBT

Fig. 3. Surface micro-morphologies of aluminum alloy under different laser oxidation powers (2000×). (a) 7 W; (b) 10 W; (c) 13 W; (d) 16 W

Fig. 4. Effect of laser oxidation power on oxygen content on aluminum alloy surface

Fig. 5. Cross-sectional morphologies of aluminum alloy under different laser surface oxidation powers

Fig. 6. Effect of oxidation power on surface roughness of aluminum alloy

Fig. 7. Joint strength under different welding powers

Fig. 8. Cross-sectional morphologies of joint under different laser jointing powers

Fig. 9. Effect of laser oxidation power on surface contact angle of aluminum alloy

Fig. 10. Effect of laser oxidation power on surface energy

Fig. 11. High-magnification Al2p XPS spectra of aluminum alloy surface. (a) Before oxidation treatment; (b) after oxidation treatment

Fig. 12. High-magnification O1s XPS spectra of aluminum alloy surface. (a) Before oxidation treatment; (b) after oxidation treatment

Fig. 13. High-magnification C1s XPS spectra of stripped PBT surface of joint under different etching time

Fig. 14. High-magnification spectra of stripped PBT surface of joint when etching time is 600 s. (a) Al2p; (b) O1s