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

Abstract

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.