Fatigue Performance of Friction Stir Weld-Bonded Al-Mg joints

The need for weight reduction and leaner manufacturing and assembly processes in aircraft construction has led to the pursuit of alternative joining processes to conventional riveting. One such technology that has been considered for this application is friction stir welding (FSW). Since it is a solid- state joining method, it results in high performing joints in a wide range of materials while avoiding overlap lengths and added weight from fasteners, crack stoppers, doublers, etc. However, the adoption of this technology to the assembly of large fuselage shell components is challenging, due to geometric tolerance management requirements. A hybrid friction stir weld-bonding method combining overlap friction stir welding and adhesive bonding (AB) has been proposed as an alternative, aims to incorporate properties and characteristics of both joining technologies, as well as improving damage tolerance. Fatigue performance of single lap joints of AA6082-T6 Al-Mg alloy was assessed and benchmarked against FSW overlap and hybrid friction stir weld-bonding joints. Significant strength and ductility increase were achieved through the hybridization of the overlap FSW joints. Fatigue strength of the hybrid joints was also higher than FSW overlap joints.