Monotonic and Cyclic Deformation Behavior of Ultrasonically Welded Hybrid Joints Between Light Metals and Carbon Fiber Reinforced Polymers (CFRP)

Abstract

In the present work, hybrid joints between the aluminum alloy 5754 and carbon fiber reinforced polyamide 66 has been joined by ultrasonic metal welding. Selected surface pre-treatments of the metallic surface were investigated to increase the joint strength and optimize the ageing behavior of the welds. Light and scanning electron microscopy were used to understand the bonding mechanisms in detail. Beside the monotonic properties especially the cyclic deformation behavior of ultrasonic welded aluminum/CFRP-joints were investigated in this work. Therefore load-increase as well as constant amplitude tests were performed with a servo-hydraulic testing system at a frequency of 5 Hz. The endurance limit of AA5754/CF-PA66-joints under cyclic tensile shear load (R > 0) was determined to about 35% of the monotonic tensile shear strength.