On 22.10.24, the successful disputation of our former research assistant Christiane Preuschoff-Gerlitzky took place. Her dissertation is entitled “A contribution to the reproducible joining of three-dimensional multi-material components by cold extrusion welding”.

In her dissertation, Ms. Preuschoff-Gerlitzky developed a process chain for the production of three-dimensional components made of steel and aluminum by cold extrusion welding, whose composite strength exceeds that of the aluminum material. As part of the work, an experimental investigation of the metal-physical bonding mechanism at the atomic level at the joint was carried out, which proved the existence of a covalent bond between iron and aluminum atoms. Based on these results, a phenomenological model was developed to describe the bond formation.

Another focus of the work was on the investigation of various surface properties and their influence on the bond strength, with carbonaceous impurities being identified as the most important influencing factor. Further numerical analyses led to the extension of the joining mechanism model to include the parameter of relative movement, which was particularly relevant for materials with different yield stresses. A theoretical model for predicting the bond strength taking this movement into account was introduced.

The knowledge gained enables the reproducible production of steel-aluminum components by cold extrusion welding. The results obtained in this work can also be transferred to other pressure welding processes, such as the joining of a hollow sphere from cylinder cups, and thus make an important contribution to the industrial application and further development of cold extrusion technology.

The PtU would like to thank Ms. Preuschoff-Gerlitzky for her many years of commitment and wishes her all the best and every success for her professional and private future.