Self-forming materials: New approaches to energy-efficient joining

In several articles in the special volume entitled "Reactive Multilayers - Micro and Macro Joining", scientists from TU Ilmenau, together with partners from Saarbrücken, Karlsruhe, Hamburg and Jülich, investigate the possibilities and challenges of reactive multilayers for micro and macro joining. The cover* of the issue, designed by Sebastian Matthes, research assistant at the Group of Materials for Electrical Engineering and Electronics at TU Ilmenau, clearly shows such a multilayer system that can be used for joining microchips.

Reactive multilayers consist of several extremely thin layers of material that react with each other in a targeted manner. As soon as a trigger - for example an electrical impulse - starts the reaction, the material releases heat. This heat is sufficient to firmly bond two materials together, for example a metal with a thermoplastic, without the need for an external heat source. This saves energy and protects sensitive components.

Reactive multilayers can open up new possibilities, particularly in electronics. They help to connect microchips, detach components without damage or even repair defective components. However, the reaction after ignition is often difficult to control. What factors influence how the reaction spreads? In the search for answers to this question, the thickness of the individual layers in particular has been analyzed to date. However, other aspects also play an important role.

Materials science students also involved in research

In several DFG-funded projects, interdisciplinary research teams from the fields of materials science, electronics technology and production engineering in Ilmenau, Saarbrücken, Karlsruhe, Hamburg and Jülich have therefore investigated further questions relating to the topic of "self-forming materials" under the leadership of Ilmenau University of Technology:

• How does the surface of the materials influence the reaction?
• What role do roughness, structure and thermal stress play?
• How can different materials and structures be combined?

In addition to doctoral students, students of materials science at TU Ilmenau were also actively involved in the research.

Prof. Anne Jung from Helmut Schmidt University Hamburg, Dr. Christoph Pauly from Saarland University in Saarbrücken and Prof. Peter Schaaf, Head of the Department of Materials in Electrical Engineering and Director of the Center for Micro- and Nanotechnologies at TU Ilmenau, explain the importance of this research in the guest editorial of the special volume Advanced Engineering Materials(DOI: 10.1002/adem.202402295). In it, they describe the potential offered by reactive multilayers as well as the challenges that still need to be solved for technical applications. Professor Peter Schaaf:

Reactive multilayers are very fast, but also very complex, so we still need to invest some research into their application.

For example, further findings, including on the basic kinetic and thermodynamic mechanisms of self-propagating reactions, could contribute at micro level to making it easier and faster to produce ever smaller microchips in future. At a macro level, the joining of batteries and contacts could, for example, increase production rates in the automotive industry.

To the special volume Advanced Engineering Materials (Volume 27, Issue 3): "Reactive Multilayers - Micro and Macro Joining"

*Cover Picture:

Sebastian Matthes et al: Tailoring the Reaction Path: External Crack Initiation in Reactive Al/Ni Multilayers. Advanced Engineering Materials. 2025. Volume 27, Issue 3. 2570009 (1 page). https://doi.org/10.1002/adem.202570009.© Copyright 2025 Wiley-VCH GmbH or related companies. All rights reserved, including rights for text and data mining and training of artificial intelligence technologies or similar technologies.