Curing-induced Distortion Mechanism in Adhesive Bonding of Aluminum AA6061-T6 and Steels

摘要

The bonding of dissimilar materials is of primary importance to the automotive industiy as it enables designers the freedom to choose from a wide variety of low density materials such as aluminum and magnesium. However, when two dissimilar materials (e.g., aluminum-to-steel) are bonded by curing at elevated temperatures, residual stresses result upon cooling the layered material system to room temperature. Problems such as distortion and fracture of adhesive often emerge in bonding of these dissimilar materials for automotive applications. In this study, the transient distortion of riveted and rivet-bonded aluminum AA6061-T6-to-steels during the curing process was investigated using the photographic method. The influences of temperature, adhesive properties, adherend thickness, adherend strength, and the presence of constraints on the transient distortion and adhesive fracture were evaluated. The peak curing temperature was found to play the most important role in distortion and adhesive fracture, followed by the influence of adherends thickness. In contrast, the other parameters studied such as the adhesive strength, constraints' type, and adherend strength produced a limited effect on distortion. The results provide useful information about vehicle body structure's design in reducing the curing induced distortion.