The aim of this subproject is to transfer and adapt the flux-free brazing processes under XHV-adequate atmosphere to the mixed aluminum-copper joint, and thus to deepen the understanding of the process. The qualification of the process is based on investigations of the mechanical and electrical properties of the joint. In addition to investigations on the wettability of the surfaces, effects leading to increased heat input into the base material will also be investigated. Other influencing factors to be investigated are the oxide layer present on the solder wire and the surface structure introduced in the deoxidation process.