Investigation of laser joining process of CFRTP and aluminum alloy

An experimental investigation on the joining process of 6061 aluminum alloy and carbon fiber reinforced thermoplastics composite (CFRTP) has been carried out with swing laser. The application of the swing laser is beneficial to obtain a larger bonding area. The effects of scanning speed are investigated on the interface formation and fracture load of the hybrid joint. In addition, the formation mechanism of the interface and the fracture mode of the hybrid joint are further elucidated. The results indicate that maximum failure load is obtained with appropriate process parameters (scanning speed: 20 mm/s, laser power: 2000 W), whereas the interface morphology under this process parameter demonstrates that the structurally sound connection between CFRTP and aluminum alloy is realized by the mechanical interlocking effect. At a higher scanning speed, the gaps in the interface caused by insufficient heat input per unit length result in a lower failure load, while at a lower scanning speed, the bubbles and gaps at the interface are observed as a result of resin decomposition and trapped pyrolysis gases in the interface, ultimately reducing the failure load of the joint. Moreover, the fracture mode of the hybrid joint is a mixed failure.