- Bundesministerium für Wirtschaft und Energie Arbeitsgemeinschaft industrieller Fördervereinigungen Otto von Guericke e.V
In many industrial sectors it is necessary to combine materials due to the different requirements on e.g. deformability or also costs. Welding, as one of the oldest and established joining processes, has proven to be very suitable, but depending on the joining component material it brings with it challenges with regard to the parameters to be selected, process control and the effects of the above on strength and corrosion resistance as well as cleanliness (in the sense of freedom from particles). In particular, problems often arise in practice when joining different types of materials.
In this project, shape memory alloys such as Nitinol are primarily to be combined with stainless steels. In practice, this poses a major problem. The joining of foreign materials is a particular challenge. The different physical properties, such as thermal conductivity, lattice structure and the formation of mixed phases and phase mixtures and their influence on the mechanical properties, make it more difficult to combine different materials without defects and cracks. In addition, sufficient corrosion resistance must be maintained for the use of such material combinations even after joining.
The aim of these investigations is to find suitable parameters for joining components made of stainless steel and nitinol by electron beam welding. Not only should the mechanical properties meet the requirements placed on the joint, but the corrosion resistance of the joint should also be guaranteed.
One application in medical technology, for example, would be the material-locking joining of guide wires for the use of catheters. These fulfil the function of positioning treatment instruments in peripheral vessels. Another area of application is tools for drilling holes to attach tendons and ligaments to bone. In both applications, requirements such as static and dynamic strength, biocompatibility, corrosion resistance, cleanliness and radiopacity must be met.