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Industrielle Versuchsanlage mit arbeitender Person.

The research field includes the atomization of liquid metal melts under inert gas with different processes to produce particles between 10 and 2000 µm and the spray compacting of deposits (up to 100 kg unit weight) of distinct geometries. Due to the atomization and the resulting high total surface area of the droplets, the solidification occurs out of equilibrium, so the microstructure and material properties considerably differ from cast materials.

As a result, alloy limitations can be overcome, in which new alloys, material composites, and gradient materials can be produced. New atomization processes are developed, analyzed, 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

Ein lächelnder Mann in einem Laborumfeld hält ein metallisches Bauteil und trägt Handschuhe.
Das Bild zeigt zwei Personen in Laborkitteln und Handschuhen, die eine große Edelstahlmaschine bedienen.
Das Bild zeigt eine Person, die eine Maschinenkomponente inspiziert und daran arbeitet.

  

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.

HM steels based on the Fe-Ti-B alloy system offer new combinations of properties for structural lightweight construction. They exhibit increased stiffness with lower density due to the precipitation of TiB2 particles from the melt. A proportion of approx. 20 % by volume leads to an increase in the stiffness/density ratio of 25 %, which enables a weight reduction of 10-20 %. However, these particles lead to severe embrittlement in conventional casting processes due to their size and sharp edges. Additive manufacturing processes offer considerable advantages here due to their high cooling rates and the resulting finer microstructure.

In the "Modulus" project, the possibility of additive manufacturing of the Fe-TiB2 system was successfully demonstrated for TiB2 proportions of 12, 15 and 20 mass % along the entire process chain. The alloys of these specific compositions produced by the MPIE were atomized into powders and pre-pressed for additive manufacturing at the IWT. Similar particle size distributions were achieved for all three materials and a triplex steel as a reference for comparison. The additive manufacturing experiments showed that it is particularly important to control the thermal history of these materials in order to achieve a low-defect state. A process window with substrate preheating was identified.

The mechanical properties determined showed that the density could be reduced by varying the TiB2 particle content, but also the properties such as hardness, tensile strength and elongation at break. It was also shown that the build-up direction has a decisive influence on the subsequent mechanical properties. With these findings, the possibilities for a transfer to industry are given.

 

The final report of the project can be obtained from the Arbeitsgemeinschaft Wärmebehandlung und Werkstofftechnik e.V. - AWT. (Postal address: Paul-Feller-Straße 1 28199).

 

Processing:
Leibniz Institute for Materials Enigineering - IWT, Bremen
Max Planck Institute for Iron Research GmbH, Düsseldorf

Duration: 01.05.2020 - 31.12.2023

 

Funding: BMWi-AiF

The IGF project 21227 N of the research association Arbeitsgemeinschaft Wärmebehandlung und Werkstofftechnik e.V. - AWT, Paul-Feller-Straße 1, 28199 Bremen, was funded via the AiF within the framework of the program for the promotion of industrial joint research (IGF) by the Federal Ministry of Economics and Climate Protection on the basis of a resolution of the German Bundestag.

 

Contact:

Dr.-Ing. Nils Ellendt
Phone: +49 421 218 64519
E-mail: ellendt(at)iwt.uni-bremen.de

Das Bild zeigt zwei Mikroskopaufnahmen von Materialien: Links ist konventionelles, gegossenes HMS (High-Strength Magnesium-Stahl) zu sehen, während rechts nanostrukturiertes HMS dargestellt ist, das durch Sprühverfahren hergestellt wurde. Rechts davon befindet sich ein Diagramm, das die Spannungs-Dehnungs-Kurve beider Materialien vergleicht.
a) Microstructure comparison of cast and spray-compacted (rapidly solidified) FeTiB alloy b) Comparison of stress-strain curves for cast (conventional) and spray-compacted (nano-structured) material
MarioCCArt: Mechanical properties and hydrogen tolerance of particle-reinforced CCA produced by additive manufacturing

For a recently introduced class of materials named High-Entropy-Alloys (HEA) the particle-strengthening effect via in-situ generation of nitrides is investigated.

Particle-reinforced HEA/CCA (High Entropy Alloys/Compositionally Complex Alloys) show outstanding mechanical characteristics in the low and high-temperature ranges. The introduced particulate inclusions influence deformation mechanisms and, hence, mechanical properties. The main objective of these investigations is to produce a material that is strong at low temperatures, fracture-resistant, fatigue-resistant, and hydrogen tolerant.

Cooperation: Universität der Bundeswehr München, Max-Planck-Institut für Eisenforschung (MPIE) 

Funding: DFG 388738622

Diagramm und Mikroskopaufnahmen, die den Einfluss von Beschichtungen auf die Materialeigenschaften veranschaulichen, einschließlich der Korngrößen und Oberflächenstrukturen von beschichteten und unbeschichteten Proben.
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: hesselmann@iwt-bremen.de

Mikroskopische Darstellung von Mikropartikeln, die mit einem Rasterelektronenmikroskop (SEM) aufgenommen wurden, zeigt eine gleichmäßige Verteilung von runden Partikeln mit einer Größe von etwa 100 µm.
SEM image of a conventionally produced aluminium powder of the sieved particle size distribution of 20-63 μm
Laser beam melting of amorphous metal powders - LaSaM

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: sbarreto@iwt.uni-bremen.de

Ein schematisches Diagramm zeigt den Prozess der Lasersynthese von Materialien, beginnend mit der Herstellung von Mikropartikeln, gefolgt von ihrer amorphen Anordnung und der Bildung von Nano- oder Mikrostrukturen.
Fig. 1: Process chain from powder production to use in laser beam melting should be controlled and optimized to produce amorphous parts
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: ufri@iwt.uni-bremen.de

M.Sc. Maike Peters
Telefon: +49421 53708 71
E-Mail:peters@mpa-bremen.de

Mikroskopische Aufnahme von Spray-Schlacke, die aus verschiedenen fragmentierten und kristallisierten Partikeln mit einer Größe von etwa 30 µm besteht.
Scanning electron microscope images: classically prepared, sharp-edged granulated blastfurnace slag (left), "spray slag" (right)
Mikroskopische Aufnahme von Spray-Schlacke, die kugelförmige Partikel mit einer Größe von etwa 30 µm zeigt, wobei einige Partikel Risse oder Brüche aufweisen.