Thermo-Mechanical Characterization of Metal–Polymer Friction Stir Composite Joints—A Full Factorial Design of Experiments

Abstract

With the increasing demand for lighter, more environmentally friendly, and affordable solutions in the mobility sector, designers and engineers are actively promoting the use of innovative integral dissimilar structures. In this field, friction stir-based technologies offer unique advantages compared with conventional joining technologies, such as mechanical fastening and adhesive bonding, which recently demonstrated promising results. In this study, an aluminum alloy and a glass fiber-reinforced polymer were friction stir joined in an overlap configuration. To assess the main effects, interactions, and influence of processing parameters on the mechanical strength and processing temperature of the fabricated joints, a full factorial design study with three factors and two levels was carried out. The design of experiments resulted in statistical models with excellent fit to the experimental data, enabling a thorough understanding of the influence of rotational speed, travel speed, and tool tilt angle on dissimilar metal-to-polymer friction stir composite joints. The mechanical strength of the composite joints ranged from 1708.1 ± 45.5 N to 3414.2 ± 317.1, while the processing temperature was between 203.6 ± 10.7 °C and 251.5 ± 9.7.

Effects of Curing Defects in Adhesive Layers on Carbon Fiber–Quartz Fiber Bonded Joint Performance

“…The bonding strength gradually decreases with the sharpening of the defect's geometric angle. This is caused by the fact that the stress concentration in the bonding zone is due to a sharp angle appearing in the process of defect morphology evolution; tip-splitting [30] easily occurs during the energy dissipation process, which leads to the initiation and propagation of cracks [32,40,41]. Meanwhile, examining various morphological defects, it can be seen that the defect has a small effect on the bonding strength at an area ratio of 1%, and the strength reduction is kept below 8.5%.…”