Laser Joining of Carbon-Fiber-Reinforced Polymer and Metal with High-Strength and Corrosion-Resistant Bonds

The combination of thermoplastic composites and metals is a critical methodology to enable the lightweight structures. Due to the high incompatibility of their physical and chemical properties, the bonding strength is always weak. In addition, the reinforced materials of composites, such as carbon fibers, which are electrically conductive and electrochemically noble, would quickly deteriorate the joint strength through galvanic corrosion. In this study, a novel laser joining process was developed for carbon-fiber-reinforced polymer and aluminum and/or steel. Methods of forming a layer that is more chemically inactive than the metal to be joined with composites, i.e. aluminum oxide on aluminum and stainless steel on steel, through laser surface texturing and cladding processes, are evaluated to improve the corrosion resistance of the joints. Furthermore, the laser-induced surface texture on the metals is created to significantly increase the initial joint strengths due to the effect of mechanical interlock. Finally, the corrosion behavior of the joints is investigated through cyclic corrosion tests and the experimental results indicate that the combination of added noble layers and textured surfaces is very promising for achieving high-strength and corrosion-resistance joints.