Friction spot joining of aluminum AA5052 and short glass fiber-reinforced PPS: Effects of material properties and process parameters on joint structure and strength

Abstract

A simplified friction spot joining (FSpJ) technique was developed to join AA5052 and short glass fiber-reinforced polyphenylene sulfide (GF-PPS) sheets. A full factorial design of experiments and analysis of variance were carried out to understand the influence of surface condition and process parameters on the joining process and mechanical strength of such joints. A maximum peak load as high as 4426.5 N was obtained. Examination of microstructures and fracture surfaces of the joints revealed important information about FSpJ joints. A microscopic serrated bonding interface at the faying interface was formed at the center of the bond, which renders a desirable bonding, together with the macroscopic interlocking produced by the interpenetration of aluminum and GF-PPS. Examination of fractured joints shows that there are two distinctive areas on a faying interface: a plastic deformation zone and a transition zone. A large number of dimples and glass fibers around these dimples were observed in fractured joints made using treated Al and GF-PPS around the center of the faying interface, which is beneficial to the bonding strength.