The research field includes the atomisation of liquid metal melts under inert gas with different processes for the production of particles between 10 and 2000 µm and the spray compacting of deposits (up to 100 kg unit weight) of different geometries. Due to the atomisation and the resulting high total surface area of the droplets, the solidification takes place in an imbalance and the microstructure and material properties differ considerably from cast materials.
This allows alloy boundaries to be shifted and new alloys, material composites, composite and gradient materials to be produced. New atomisation processes are developed, analysed and used for the production of metal powders and deposits. Thermal simulation of the processes supports process understanding and facilitates up-scaling. The experimental work includes investigations and developments of different base alloys (Fe, Al, Cu, Sn, Ni, Co, Si).
Projects
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
Contact:
M.Sc. Daniel Knoop / Farhad Mostaghimi
Tel.: +49421 218 51435
E-Mail: dknoopiwt-bremende
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.
Considering the entire process chain from the powder production to the tested component, the project is divided into the following steps:
- Alloy development according to the requirements of the components
- Development of atomization facility followed by production and characterization of the powders
- Development of the selective laser melting process for high-strength aluminum alloys
- Heat treatment strategies for components made of high-strength aluminum alloys
- Testing of manufactured components
The heat treatment studies focus on its effects on the mechanical properties of the components and the control of distortion.
Editing: WT-LW, IWT-VT
Funding: ZIM 16KN021235
Contact:
M.Sc. Eric Gärtner
Telefon: +49421 218 64502
E-Mail: e.gaertneriwt.uni-bremende
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
Contact:
M.Sc. Eric Gärtner
Phone: +49421 218 64502
E-mail: e.gaertneriwt.uni-bremende
Pegasus - Development of a pressure gas atomization process for a cost and material efficient production of aluminum alloy powder for additive manufacturing
Within the project “Pegasus” a novel pressure-gas-atomization process (PGA) will be developed to significantly increase the cost and material efficiency in the production and processing of aluminum powders.
The potentially narrower particle size distribution of powders produced by PGA increases material efficiency and could thus create both ecological and economic advantages compared to conventional technology. In order to evaluate these effects, the produced aluminum alloys will be investigated with respect to their suitability for additive manufacturing. The focus is mainly on the characterization and processing of temperature sensitive powder alloys.
Editing: IWT-VT / WT
Funding: BMWI-AiF/ZIM
Contact:
M.Sc. Marcel Hesselmann
Tel.: 0421 218-64549
E-Mail: hesselmanniwt-bremende
Laser beam melting of amorphous metal powder – development of a synergetic value chain through holistic process optimization
The LaSaM project intends to broaden the production of bulk metallic glasses (BMGs) by laser beam melting (LPBF) and expand their economic applicability.
The greatest challenge is to avoid crystallization along the entire process chain from powder production to use in LPBF to maintain the superior properties of BMGs. The main goal is to produce amorphous components made of CuTi-based alloys by LPBF and to gain knowledge about the oxygen intake and cooling behaviour taking place during the process, as they could lead to crystallization. This will allow extending the narrow process windows for defect-free processing and the adaptation of the technology to new product geometries. The project is a cooperation with the University of Saarland and the University of Duisburg-Essen.
Editing: IWT-VT
Funding IGF No.: 21227 N
Contact:
M.Sc. Erika Soares Barreto
Tel.: +49421 218 51404
E-Mail: sbarretoiwt.uni-bremende
Spray slag - processing liquid blast furnace slags to produce low-CO2-emission hydraulically bound building materials
The aim of the project is to use blast furnace slags, which are used in the production of cement in the form of granulated blast furnace slag, even more effectively.
To this end, the blast furnace slags are to be sprayed particularly finely while still in a molten state using an innovative spraying technique in order to avoid the time-consuming grinding process and to use the advantages of the ideally round grain shape of the blast furnace slag balls in modern and environmentally friendly concretes.
The high viscosity of blast furnace slags leads to undesirable fibres during atomisation. This is to be counteracted, among other things, by increasing the atomiser gas temperature in order to increase the yield of desired round particles.
On the one hand, this eliminates the need for granulating, drying and very energy-intensive grinding of the blast furnace slags to produce granulated blast furnace slags. On the other hand, the expected ideally round particle shape of the sprayed blast furnace slags means that concretes with a lower cement demand can be expected than when using classic cements containing blast furnace slag. Both savings potentials lead to the expectation of a considerable reduction of previously occurring CO2 emissions in the entire production chain of structural concrete.
Working on the project: IWT-WT-MPA-Bauwesen / IWT-VT
Funding: AUF programme for the promotion of applied environmental research with funds from the ERDF and the State of Bremen, funding code: AUF0014B
This project is funded by the European Regional Development Fund (ERDF).
Cooperation partner: HS Bremen, Institute for Building Materials Technology
Kontakt:
Prof. Dr.-Ing. Udo Fritsching
Telefon: +49 (0)421 218-51230
Email: ufriiwt.uni-bremende
M.Sc. Maike Peters
Telefon: +49421 53708 71
E-Mail: peters@mpa-bremen.de
AiF Project MODULUS: High modulus steels for the additive manufacturing of lightweight components
The main objective of this project is to develop a rapid solidification process through powder atomization and additive manufacturing (AM) routes for production of nano-structured high modulus steel (Fe-TiB2) in a cooperation with Max-Planck-Institut für Eisenforschung MPIE, Düsseldorf.
The stiff and light TiB2 particles in the Fe-based metal matrix composite (MMC) induces higher stiffness / density ratio, which enables a weight saving of up to 10 – 20% depending on the component. However, the conventional liquid-metallurgical casting process results in severe embrittlement due to very large (several µm diameter) and sharp-edged particles. Through the rapid solidification process this negative effect can be significantly reduced. For example, through spray forming process a factor of approx. 100 (nano-scale particles) have been achieved. The finely divided precipitations lead to a substantial improvement in the mechanical properties. The tensile strength increases by approx. 60%, with the elongation at break only decreasing insignificantly. In addition, the modulus of elasticity decreases slightly. In this project a process chain will be developed with ideal parameters for industrial use, for example in drive components.
Editing: IWT-VT, MPIE
Funding: Projekt IGF 21460
