Microstructure modification by thermomechanical processing of materials in joining-, coating- and forming processes, tailored to the respective application area, are the focus of the research work within the LM Group. By modifying the microstructure, properties of base materials are tailored for the requirements in targeted applications. Higher strength, local reinforcement as well as higher local damage tolerance can be specifically tuned. Research and development is carried out at the LM Workgroup on in-house developed equipment. The process expertise of the LM Group includes the Hybrid Friction Diffusion Bonding (HFDB) developed at Hereon and, together with LINDE AG, patented in a variant for coil wound heat exchangers (CWHE), as well as friction surfacing (FS) and friction extrusion (FE).
The LM Group is engaged in process development from basic up to application related research in the areas of hybrid friction diffusion bonding (HFDB), friction surfacing (FS) and recently friction extrusion (FE).
The work of the group aims at industrial sectors including the energy sector (HFDB) for e.g. low and high temperature heat exchangers, the shipbuilding sector (HFDB, FS) for e.g. dissimilar multi-material joints, as well as the commercial aircraft sector (HFDB, FS, FE) for e.g. increasing the damage tolerance of metallic aircraft structures through thermomechanical processing.
HFDB is a friction based process used in its standard form to join thin sheets or thin sheets on substrates in overlap as well as, through slight adaption of the HFDB tool alignment, in butt joint configuration.
A variant of the HFDB process has been specifically developed in close cooperation with the LINDE AG for tube-to-tube sheet connections in large heat exchangers.
FS is a solid-state joining method used to deposit coatings on a substrate involving frictional heating and severe plastic deformation, which leads to fine grained, non-equilibrium microstructures.
FE is investigated with the aim of producing controlled ultra-fine grained microstructures by using frictional heating in conjunction with severe plastic deformation. FE produced materials can be used for structural applications which require high strength, high ductility materials e.g. high strength lightweight bolts and fastener in the aircraft and space industry.
The scalability of the above mentioned processes as well as the idea of a future implementation into a downscaled demo system shall incorporate ideas concerning “one button processing / manufacturing”. In the course of a deeper automation / integration this shall lead into manufacturing processes as postulated in “Industrie 4.0” as well as a possible automated data distribution into post-processing / pre-processing process simulation / feedback systems for scientific use.
Since February 2017, Dr.-Ing. Arne Roos is newly appointed head of the Local Modification (LM) Group at WMP. Research is conducted with support through BSc, MSc and PhD Students in the course of short term contracts as well as support through the use of Hereon / WM infrastructure.