Ultrasonic Vibration-Strengthened Adhesive Bonding of CFRP/Aluminum Alloy Joints with Anodizing Pretreatment

Ultrasonic vibration has been applied to improve the penetration of adhesive into the anodized layer, thereby enhancing the strength of carbon fiber-reinforced plastic/aluminum alloy bonding joints with anodizing pretreatment. The ultrasonic vibration-assisted adhesive bonding process was designed by orthogonal experiments, then verified experimentally. The strengthening mechanism was studied by analyzing the morphology and elemental distribution of the cross-section of the joint. The results show that the ultrasonic vibration-assisted adhesive bonding process can further strengthen the interfacial bonding. For the studied joints, the strength can reach 18.66 MPa, being 55% higher than without ultrasonic strengthening. The ultrasonic vibration creates shock waves in the adhesive layer, causing a high-speed adhesive jet toward the adherend surface, which makes the interfacial bonding tight and promotes penetration of the adhesive into the anodized layer. The bonding strength is thereby remarkably improved by forming a larger interfacial contact area and more mechanically interlocked structures.