Friction-Riveted Hybrid Joints of Short Glass Fiber-Reinforced Polyamide 6 and 6056-T6 Aluminum Alloy

Hybrid joints of short glass fiber‐reinforced polyamide 6 and 6056‐T6 aluminum alloy (PA6‐30GF/AA6056‐T6) are produced by friction riveting under different processing conditions. A comprehensive study of the effects of the processing parameters on the temperature evolution, anchoring efficiency, degradation of the polymer composite, and tensile strength (pullout test) of the joints is performed. With higher values for the rotational speed, spindle displacement, and joining force, the heat input is increased and this results in greater deformation of the rivet tip and thus higher anchoring efficiency. Based on this finding, high‐strength joints with tensile strength (pullout test) of up to 93% of the metal rivet are obtained and failure occurred through the ductile fracture of the metal rivet outside the composite plate region. Process‐related degradation of the polymer composite is identified, with the formation of voids in the polymer thermo‐mechanically affected zone (PTMAZ) as well as PA6 chain scission and glass fiber breakage in the rubbing volume around the rivet. The recrystallization of the PA6 matrix in the PTMAZ is not affected by the processing. Degradation of the composite at the polymer‐metal interface does not reduce the quasi‐static tensile strength (pullout test), although it may affect the long‐term mechanical properties of the joint