Composite materials are more and more widely used in the automotive industry with the increasing requirements of lightweight design. In order to obtain automotive parts with excellent comprehensive mechanical properties, the 7075-T6 aluminum alloy was integrated with Carbon Fiber Reinforced Plastic (CFRP) by using thermoforming process. The influence of four forming methods on the forming process, forming accuracy, and interface bonding strength was studied in this work. A finite element model based on cohesion and forming was established to study the integrated thermoforming and properties prediction of Al/CFRP hybrid composites. The results showed that forming CFRP and unformed 7075 Al aluminum alloy sheet together required higher forming energy and the formed parts had higher Mises stresses. When the CFRP was located below 7075 aluminum alloy sheet, the uneven stress distribution due to the severe deformation of the resin resulted in the worst forming accuracy. For all four processes, the thickness of the formed parts decreased at the round corners and side wall area, increased at the flange area, and changed little at bottom surface. The thickness distribution of the formed part depends on the deformation process and the contact pressure between the tools and the blank. Greater contact pressure resulted in greater thinning rate. For the processes of preformed 7075 aluminum alloy, although less forming force was needed, the interface debonding risk between 7075 aluminum alloy and CFRP might arise due to the small contact pressure.

With the increasing requirements of automotive lightweighting, metal/CFRP laminates are increasingly used. In this paper, Al/CFRP laminates were prepared using an integrated hot press curing method, and the optimum curing conditions were determined using the single-lap shear test at 130 °C for 45 min. The effects of fiber lay-up, forming speed, and metal layer thickness on bending springback were investigated using the V-shaped bending test and Abaqus finite element analysis method. The results show that fiber lay-up has an important influence on springback. Among the five different fiber lay-ups (0° unidirectional, 90° unidirectional, 0° orthotropic, 90° orthotropic, and 45° orthotropic), the 45° orthotropic lay-up had the lowest springback rate of 1.11%. Increasing the thickness of the sheet metal can significantly reduce the resilience rate. As the sheet thickness increased from 2 mm to 3 mm, the springback of the 90° unidirectional lay-up decreased by 43%. Springback was not sensitive to forming speed, and the difference in springback was within 1% at different forming speeds. The damage behavior of the forming process was analyzed using the three-dimensional Hashin damage law with the Vumat subroutine and microscopic analysis. Fiber and resin damage under 45° orthotropic lay-up conditions was relatively small compared to fiber damage under 0° unidirectional lay-up and resin damage under 90° unidirectional lay-up.