The following projects have already been worked on within the framework of our research focus "Additive Manufacturing":
SPP2122 Materials for Additive Manufacturing
Qualification of new steel-alloying strategies for LAM powders by combined in-situ additivation, agglomeration and in-/post-process treatment
The main objective of Priority Programme 2122, funded by the German Research Foundation (DFG), is the synthesis of new metal and polymer powders for efficient laser-based additive manufacturing through formulations, additivation and (chemical) modification of new and commercial powders. This should significantly expand the choice for powder materials accessible to laser-based additive manufacturing (LAM). Improving processability includes requirements such as efficient, low-cycle, highly reproducible and precise laser-based additive manufacturing processes.
One of the eleven sub-projects is the tandem project "Qualification of new steel-alloying strategies for LAM powders by combined in-situ additivation, agglomeration and in-/post-process treatment" in cooperation of the Leibniz Institute for Materials Oriented Technologies - IWT with the University of Bochum - Chair of Materials Technology (LWT) and the University of Dortmund - Department of Materials Testing Technology (WPT). The main objective of the project is the development of new starting materials for additive manufacturing and their qualification for the processing of martensitic, hardenable tool steels or cast iron by LAM.
By mixing iron and ferroalloy powders, the content of certain elements such as Cr, Mn, Ni is to be increased in order to produce, for example, white cast iron and ledeburitic cold work steels. Mixtures of ferroalloy powders and pure elements, which are conditioned by agglomeration into flowable powders, are also to be processed in a similar way. It is assumed that similar alloys or chemical compositions, despite the different processing routes, can achieve equivalent properties of the powders.
This would mean that only a few base powders with different chemical compositions are needed to produce several alloys. Laser-based additive manufacturing can significantly accelerate the development of new alloys due to economic and procedural advantages, as the microstructure formation process and the associated formation of internal defects can be decoupled from the LAM densification process.
To deal with the complex material-oriented research within SPP 2122, all aspects are addressed in a holistic approach regarding powder production, conditioning and processing (IWT), alloy design and microstructure investigation of the designed powders (LWT) as well as microstructural, micro-magnetic and mechanical characterisation of the SLM components (WPT).
Further information on the sub-project or the overall project SPP 2122 can be found here.
One of the publications on the project can be found here.
M.Sc. Anna Strauch
Phone: +49421 218 51327
HIP⁴AM - Hot-Isostatic Pressing for Additive Manufacturing
As part of the project "Hot-Isostatic Pressing for Additive Manufacturing - HIP⁴AM", the process chain for additive manufacturing (3D printing) of high-strength metallic components was completed at Leibniz-IWT Bremen through the procurement of a hot-isostatic press.
The press allows heat treatment up to 1400°C under an isostatic gas pressure of up to 2070 bar. In combination with the integrated quenching capability, the development of combined HIP heat treatment processes is possible.
The system complements the institute's existing continuous process chain of additive manufacturing from powder to tested component and enables the investigation of the technological potential of these processes. The procurement was supported with funding from the ERDF program Bremen 2014-2020.
Bearbeitung: WT-LW, WT-WB, ECOMAT
Förderung: EFRE-Programm Bremen 2014-2020
Laufzeit: 04/2019 – 04/2021
M.Sc. Daniel Knoop
@ALL – Additive Manufacturing for Aluminum Launcher Structures
In the aerospace research project, the additive manufacturing of secondary structures in launcher vehicles made of high-strength aluminum alloys was a central theme.
The focus was on the industrialization of the existing alloy Scalmalloy® as well as the development of completely new, less expensive and yet high-strength aluminum alloys. Investigations along the entire additive process chain, from powder production through LPBF processing to materials testing, enabled a comprehensive understanding of the additive processability and the material mechanisms. Furthermore, two demonstrator structures were subjected to topology optimization with regard to the geometric freedom and subsequently manufactured using LPBF.
This project was funded by the European Regional Development Fund (ERDF).
The project was successfully completed in November 2020.
Editing: IWT-WT / VT
Funding: EFRE-LURAFO 1010A
M.Sc. Marcel Hesselmann
Tel.: 0421 218-64549
Properties of additive manufactured nitrogen steels (Add FeN I)
Laser powder bed fusion (L-PBF) of Cr- and CrMn-steels with high amount of nitrogen, which could be used to produce Ni-free medical devices, is of great interest to the medical industry.
However, due to the lack of knowledge only a small group of steel powders are currently available for this application. In this project nitrogen is added to the tool steels via gas atomization under nitrogen atmosphere and gas nitriding of the powders. The resulting powders are examined with regard to nitrogen concentration, particle size and shape, and microstructure. The powders can be successfully processed in L-PBF due to good flowability and packing density.
Editing: IWT-VT, IWT-WT, RUB, TU Dortmund University
Funding: DFG Zo 140/22-1
Dr. Chengsong Cui
Tel.: +49421 218 51404
Fatigue strength of by selective laser melting generated samples
As a relatively new growing technology, compared to conventional generation methods additive manufacturing process holds advantages in its feasibility of complex design, its time and cost saving features etc.
On the other hand, components generated by additive manufacturing possess more amounts of pores, which highly request for investigation of the corresponding mechanical properties. For structural components, their mechanical behaviors under static and dynamic loadings are of high importance, however, the one under dynamic loading are not yet extensively studied. In this cooperative project, tensile and fatigue strength, as well as underlying fracture mechanisms and damage origins for austenite and tool steels generated by selective laser melting are the investigation goals.
Dr.-Ing. Jens Schumacher
Telefon: +49421 218 51375
Characterization and modeling of multiple phase transformation in tool steels during additive manufacturing
Laser Powder Cladding (LPC) is one of additive manufacturing (AM) techniques.
For the production of metallic components by LPC the knowledge and control of the microstructure are key issues. To gain knowledge about microstructural evolution during the LPC process synchrotron XRD technique was applied and the results showed that the deposited layers are re-melted, re-austenitized and re-quenched differently depending on the height positions due to the deposition of new layers on top.
Editing: IWT-WT-PA/WB, BIAS, ZeTeM/University of Bremen
CustoMat3D – Tailored LAM-aluminum alloys for highly functional, multi-variant structural automotive components
Aim of the project CustoMat3D is to develop a simulation-based, material-specific laser additive manufacturing (LAM) process chain for the automotive industry.
In concrete terms, new aluminum alloys for LAM shall be developed, which meet the automotive-specific requirements for strength, crash, part quality, etc. Finally, the process chain of highly functional vehicle structures shall be validated.
The IWT is responsible for the development of tailor-made aluminum materials for LAM production. An alloying concept was developed which uses the fast cooling rates in the LAM process to provide a competitive alternative to widely used materials. The suitability of the material was demonstrated using structural and chassis components for automotive applications.
Editing: WT-LW, VT-SK, EDAG Engineering GmbH, Concept Laser GmbH, Mercedes-Benz AG, ECKA Granules Germany GmbH, Fraunhofer Institute for Industrial Mathematics ITWM, Fraunhofer Research Institution for Additive Production Technologies IAPT, MAGMA Gießereitechnologie GmbH
Funding: BMBF ProMat_3D 03XP0101G
Duration: 02/2017 - 01/2020
M.Sc. Daniel Knoop / Farhad Mostaghimi
Tel.: +49421 218 51435
StaVari - Additive manufacturing of complex products in variable and highly functional steel structures
The aim of this collaborative research project is the development of a process chain for the laser additive manufacturing (LAM) of steel structures for the automotive and medical industry.
The main goal is to demonstrate the feasibility of highly functional and complex LAM-components and their combination options with conventional semi-finished parts. The IWT determined the alloy concept medium manganese steel (about 5-12 % Mn) with several variations, developed the powder spray forming process successfully and is working on a suitable heat treatment for the additive manufactured parts. Due to the multidisciplinary tasks, the two IWT main departments “Material Science” and “Process and Chemical Engineering” work closely together.
Editing: IWT-WT-LW, IWT-VT-SK
Funding: BMBF 02P15B052
Cooperation partners: EDAG Engineering GmbH, Ziehm Imaging GmbH, Salzgitter Mannesmann Forschung GmbH, Indutherm Gießtechnologie GmbH, Concept Laser GmbH, Carl Cloos Schweißtechnik GmbH, Hema Electronic GmbH, Leibnitz Institute for Material-Oriented Technologies, Fraunhofer Research Institution for Additive Production Technologies IAPT, Chemnitz University of Technology, Chair of Lightweight Structures and Plastics Processing
M.Sc. Lena Heemann / Farhad Mostaghimi
Phone: +49421 218 51414
Additive manufacturing of high-entropy-alloys (HEA) (PaCCman)
For a recently introduced class of materials named High-Entropy-Alloys (HEA) the particle-strengthening effect via in-situ generation of nitrides is investigated.
By N2 flushing of metal melts and subsequent rapid solidification by means of gas atomisation, powders with a high N2 content of up to 0.2 wt. % can be produced. The synthesised powders are subsequently additively manufactured into cm-scale samples, formed and heat-treated. The influence of the individual process steps on the strengthening mechanisms and microstructure formation are the aim of the investigation. Using the example of a CoCrFeNi alloy, a positive influence of particle reinforcement on the micromechanics of the metallic powders produced and samples manufactured by L-PBF (laser-powder-bed-fusion) could be demonstrated. Furthermore, powders whose processability was not given in the L-PBF application process were improved by means of nanoscale additives of the type so that an optimal flowability was achieved. This powder conditioning step enables the use of the fine fraction < 20 µm in the L-PBF process and leads to an enormous yield increase of approx. 20 %. Flow-improving effect of nanoparticulate coatings on metal powders for additive manufacturing using the example of the dynamic angle of repose for CoCrFeNi powders.
Editing: VT SPK
Partner: MPI Iron Research, Düsseldorf
Funding: German Research Foundation in the Priority Programme 2006 "Alloys with Complex Composition - High Entropy Alloys (CCA-HEA); funding code: UH77/11-1
M.Sc. Eric Gärtner
Phone: +49421 218 64502
LHASa - Laser additive manufacturing of high-strength aluminum structures
The aim of this project is the additive manufacturing of components made of high-strength aluminum alloys.
The complete process chain from powder production to the tested component is considered, with the project being divided into the following sub-steps:
- Alloy development according to the component requirements
- Development of a powder atomization system as well as powder production and characterization
- Process development of the laser beam melting process for high-strength Al alloys
- Heat treatment strategies for components made of high-strength Al alloys
- Tests of the manufactured components
The heat treatment investigations focus on the influence of the treatment on the mechanical properties of the components and the control of distortion.
Editing: WT-LW, IWT-VT
Funding: ZIM 16KN021235
Dr.-Ing. Anastasiya Tönjes
Phone: +49421 218 51491