Hybrid composites of metal and polymer enable adapted component requirements, such as an improved load transmission, an increased stiffness, an optimized corrosion behavior or an adapted damping capacity. However, these metal-polymer hybrid structures are also convincing due to their high material and energy efficiency. In line with this demand, joining technologies are confronted with new challenges, as the individual components require material-specific and aligned thermal-rheological conditions for joining these hybrid parts simultaneously.
The aim of the present investigations was to investigate the applicability of laser beam and TIG welding for these metal-polymer hybrids. While both processes have a high degree of maturity for joining single material, they are unsuitable for joining thermoplastics under the given conditions. The idea behind is to ensure a material-compatible joining of the inner polymer layer by using heat conduction effects during the joining of the metallic components. The requirements for this are a targeted process regulation as well as an adjusted part design.
The investigations show that the energy-affected zone and the power density during thermal joining of the metal-polymer hybrid structures have a significant influence on the joint quality. At the same time, the interface between metal and polymer is highly stressed due to the power density. Compared to TIG welding, laser welding allows a more controlled energy input. Nevertheless, due to the comparatively small energy-affected zone, disadvantages regarding the weld seam quality of the polymer layer appeared. The examinations impressively show that it is technically possible to join metal-polymer hybrid structures by using a single joining process. However, the central challenge is the regulation and adaptation of the process as well as the design of the joining area. For this purpose, the presentation will show first approaches and basic results.