Laser Joining Technologies for Dissimilar Material Combinations

The combination of dissimilar material combinations is a challenging goal for the development of parts with locally optimized properties. The main goal of these developments are weight reduction, properties optimization or the tailoring of properties for specific applications in combination with an efficient joining technology. However, using conventional high temperature joining technologies the formation of intermetallic phases within the joining zone is a nearly unavoidable phenomenon when joining dissimilar material combinations. These phases cause a lack of the mechanical stability in the joining zone. By using an optimized laser joining technology for thin sheet materials this problem could be overcome. The localized energy input of the laser beam and a controlled heat distribution leads to minimized interaction of the joint materials. To overcome process instabilities special working heads were developed. At present, Fe/Al and Ti/Al material combinations were successfully joined by this process.

Metallurgical and mechanical properties of a number of selected dissimilar material joints will be presented and some applications discussed.