Profile
The department Solid State Joining Processes is part of the Institute of Materials Research and works on basic- and application oriented research topics in the area of friction welding for joining and coating. The research activities in this area comprise the following processes:
- Friction Stir Welding - FSW
- Friction Stir Spot Welding – FSSW
- Friction Spot Welding – FSpW
- Friction Hydro Pillar Processing - FHPP
- Friction Surfacing
- Rotational Friction Welding
- Fric Riveting
- Injection Clinching Joining
Since the beginning of the 90’s, the department Solid State Joining Processes works on friction based processes. In this context, first investigated were radial friction welded Ti and Steel materials (especially for the welding of pipelines). In the middle of the 90’s, the group took up Friction Hydro Pillar Processing (FHPP) and the stud welding, with emphasis on Ti- and steel materials. At the same time, the first investigations were initiated on Friction Surfacing, which comprises a wider selection of materials (Ti-, Ni- und Al-alloys, NiAl-bronze und corrosion resistant steels). In 1996 started the R&D activities with the friction stir process (FSW). Then In 1999, the Friction Stir Spot Welding (FSSW) and the Friction Spot Welding (FSP) were filed for patent. In the last years, three new processes were developed, which currently are investigated in the context of two doctoral theses: Hybrid Friction-Diffusion Bonding (HFDB), FricRiveting and Injection Clinching Joining (ICJ).
For FSW and associated processes, foremost Al- und Mg-alloys and very hard steels are used, whereby Ti- alloys and corrosion resistant steels (for HFDB) and Polymers (for FricRiveting und ICJ) act as joining partners. With exception of the ICJ-process, all above mentioned joining processes are based on similar physical and metallurgical processes. This singularity allows a simple depiction of the relevant scientific topics. (Please refer to Tabelle 1).
For FSW and associated processes, foremost Al- und Mg-alloys and very hard steels are used, whereby Ti- alloys and corrosion resistant steels (for HFDB) and Polymers (for FricRiveting und ICJ) act as joining partners. With exception of the ICJ-process, all above mentioned joining processes are based on similar physical and metallurgical processes. This singularity allows a simple depiction of the relevant scientific topics. (Please refer to Tabelle 1).
With the formulation of technological solutions and concepts for joining challenges for the national and European industry, a significant contribution is made in the programme topic "Mechanics and Joining of Light-Weight Materials" of the programme "Advanced Engineering Materials” within Helmholtz-Research-Area "Key Technologies ".
Table 1 – Scientific topics in the area material, process, and properties for the group Solid State Joining Processes.
| Metallurgy | Processes | Properties |
| High Temperature Plasticity | Understanding Bonding Processes | Determination of Properties |
| Recovery and Re-crystallisation | Energy Balance for Solid State Joining Processes | Failure Mechanisms of welds |
| Non Plasticity | Eigenspannung und Verzug | |
| Exclusion processes | ||
| Phase Change | ||
| Diffusion Processes | ||
| Interfaces and Surface Processes |
The technological topics are tightly connected to the scientific topics and are normally investigated together with industrial partners (Table 2)
Table 2 –Technological topics for the group Solid State Joining Processes
| Technological Topics | |
| FSW: | *Investigations on weldability of hybrids: Steel/Mg-alloys, Steell/Al-alloys *Failure development mechanisms for FSW of Al-alloys *Repair of FSW-welds *Development of Bobbin-Tool-Technology for Al-alloys *Plastic deformation of FSW-welds *Productivity increases for FSW (High Speed FSW) *Investigation of the weldability of modern steels with FSW |
| Friction Stir Processing: | Functionalisation of surfaces |
| Polymer Metal Joints: | Process technology and parameters of the welds |
| FHPP of light weight metals: | Process technology and parameters of the welds |
| Friction Surfacing: | Development of laminate materials and relevant process technology |
| Hybrid Friction-Diffusion Bonding (HFDB): | Process technology and parameters of the welds |
| Friction Spot Welding: | Process technology and parameter of the welds |