Improvement of the laser joining of CFRP and aluminum via laser pre-treatment

Fiber laser was used to join aluminum alloy (A7050) and carbon fiber reinforced plastic (CFRP). In the paper, the research was focused on evaluating the effect of laser Surfi-Sculpt process on the shear strength of A7050 and CFRP joint. The interface microstructure and fracture morphology of A7050/CFRP joint were observed by optical microscope and scanning electron microscopy, and the shear strength of dissimilar joint was tested by Gleeble machine. The result indicates that the pre-treatment of A7050 with the laser Surfi-Sculpt process could improve the shear strength of the dissimilar joint to a large extent. For the A7050/CFRP dissimilar joint without the pre-treatment, the highest shear strength of only 8.5 MPa could be attained. In contrast, when the A7050 was pre-treated by the laser Surfi-Sculpt, the shear strength increased to 39.0 MPa, which was over four times that of the previous joint without the pre-treatment. Finally, both the bonding mechanism and failure mechanism of this dissimilar joint were investigated.