Laser surface processing enables lightweight and additive-free hybrid material structures with high bond strength

The application of lightweight structures in the aerospace and automotive industry has been significantly increasing in the past years and tends to slowly pave its way into mass production. Fiber-reinforced plastics (FRP) enable, in combination with metal structures, the production of resource-saving as well as more efficient vehicles and therefore lead to a better carbon dioxide balance.
To be able to build hybrid vehicle structures from components made of dissimilar materials such as fiber reinforced plastic and metal, new tailor-made joining processes are needed. Conventional metal joining processes currently used for industrial applications, such as welding, adhesive joining or mechanical joining processes such as riveting are not meeting all requirements. These techniques are either not suitable (welding of dissimilar materials) or rely on the use of additional materials (adhesives), which make it signifi-cantly more difficult for the assemblies to be fully recycled.
The design and properties of the interface between the dissimilar materials are crucial for a reliable additive-free connection with high bond strength. Short pulsed lasers are able to structure and modify surfaces of numerous materials in various ways. Thus laser surface processing is a promising technique for interface modification enabling durable direct material joints for hybrid lightweight structures.
In our poster, we present latest results of how laser-structured surfaces increase the bond strength of hybrid joints made of metal and fiber-reinforced plastics. Results show mechanical strengths several times higher than reference processes. The presentation focuses on the following connections:
• Laser-structured metal components and glass-fiber reinforced thermoplastic composites directly joined by consolidation under increased temperature and pressure
• Composite profiles made of laser-structured metal elements and glass-fiber reinforced plastic realized in a pultrusion process
• Components made of laser-patterned fiber-reinforced plastic with added 3D-printed geometries.
The results of the research open up new possibilities for more sustainable and resilient lightweight structures.