Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM
Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM

Material concepts

Metallic materials with tailored properties

Powder metallurgical technologies offer unique opportunities to realize properties and special property combinations in materials and components. The focus of our developments is on improving and expanding the range of properties of materials and components as well as their economical and resource-saving production.

The wide range of powder metallurgical manufacturing options are used for a wide variety of material developments or are specifically further developed or adapted. Here, we present some of the material concepts that are the focus of our research work.

Electrode materials

 

Electrodes are the key components of any electrochemical reactor. At Fraunhofer IFAM, we develop, manufacture, and test electrodes for various applications, e. g. for hydrogen production or CO2 conversion. In a specially designed laboratory electrolyzer, the applicability of the electrodes can be tested under realistic conditions of an alkaline electrolyzer.

High-temperature materials

 

In times of ever-increasing requirements – especially with regard to the operating temperature –materials that can withstand the highest thermomechanical stresses are constantly in the focus of materials research. At our institute, material systems are investigated which are to be produced preferably or exclusively via powder metallurgical routes. This includes the production of corresponding powders as well as their processing into semi-finished products or finished components.


Composite materials

 

Composite materials are materials that are composed of at least two different materials. The material system has improved or completely new properties compared to the individual materials. The development, shaping, and application of composites are the research topics at Fraunhofer IFAM. In particular, the focus is on particle and fiber composites, most of which have a very high filler content. However, metal-ceramic interpenetration composites, in which at least two respective coherent phases interpenetrate each other, are also the subject of current investigations.

Lightweight metals

 

The continuing demand – particularly from the automotive industry – for consistent use of lightweight materials and molds to reduce the weight of vehicles opens up interesting possibilities for the use of powder-metallurgical aluminum components. The traditional processing of powder mixtures in the molding process (pressing – sintering – calibrating) enables complex components to be manufactured with final contour and tolerance accuracy. Today, the successful development of press-ready powder mixtures (e. g. wear-resistant aluminum sintered materials containing hard materials) and of new sintering technologies (e. g. SLPS sintering) allows the mass production of components that are already in use for some applications.

Magnetic materials

 

In shaping soft magnetic composites (SMCs), the institute draws on its many years of experience in powder metallurgy. The powder-based functional materials are particularly suitable for conducting and amplifying magnetic fluxes and, in contrast to conventional Fe-based alloys, are also suitable for use at high frequencies. However, for weight and installation space reasons, the energy density of the hard or even permanent magnets is decisive for many applications. Fraunhofer IFAM is working on the resource-saving and economical production of complex Nd-Fe-B magnets. For this purpose, metal powder injection molding has been adapted for the production of rare earth magnets. The process enables the manufacture of complex, near-net-shape components with only a few process steps. 

Magnetocaloric materials

 

Magnetic cooling is a new, powerful and environmentally friendly technology with the potential to reduce energy consumption by about 30 % compared to conventional compression cooling. The technology is based on the magnetocaloric effect (MCE), which is the change in temperature of a material as a function of the applied magnetic field. In this context, heat transfer from the magnetocaloric material is a critical factor for the potential performance and efficiency of a magnetocaloric system. In order to optimize this, the aim is to shape the magnetocaloric material into thin-walled heat exchanger structures with wall thicknesses of less than 500 µm. To this end, Fraunhofer IFAM is optimizing the manufacturing processes of metal powder injection molding, extrusion, or laser melting for the specific requirements of magnetocaloric materials.

Metal hydrides for reversible H2 storage

 

Metal hydrides are solid-state hydrogen storage materials that can be used in a wide range of applications such as high-purity hydrogen storage or thermochemical hydrogen compression. Recent technological advances by Fraunhofer IFAM demonstrate that metal hydride composites offer several advantages over conventional metal hydrides, e. g. full charge-discharge cycle times of a few minutes.

Metal Matrix Composites

 

Metal matrix composites (MMC) offer unique combinations of properties. This group of materials becomes interesting for structural and functional applications whenever the property profile of conventional materials can no longer meet the requirements. Powder metallurgical manufacturing processes have a high application potential due to the feasibility of a wide variety of material combinations. In addition to high flexibility in the selection of matrix alloy and reinforcing component, there are only minor limitations in the size and geometry of the particles and short fibers.


Metal foams, cellular metallic materials and composite foams

 

Cellular metallic materials represent a class of materials which, in addition to light metals, contribute to weight reduction, whereby the mass saving is achieved by the defined incorporation of pores. With this focus, novel lightweight materials have been developed in recent years. In addition to a drastic mass and thus material saving, cellular metallic materials can realize further application-specific properties, which are determined in particular by the material and the cell structure, such as sound absorption, heat insulation, energy absorption, mechanical damping, mass and energy transport or catalytic effects.

Sintered and composite materials

 

Alloys, composites, material composites and structural materials with the required property profiles can be produced by mixing powders. The combination of properties can often be directly derived and realized by powder composites, taking into account the thermodynamic boundary conditions. Thus, properties such as hardness, toughness, Young's modulus, wear and thermal expansion can be adapted to the requirements. It is also possible to vary the density from continuous porosity to complete density in a component. During sintering, the component made from molded powder then acquires its final properties.

Composites by means of thermal joining processes

 

Constantly increasing requirements in terms of functionality, stability and weight indicate a clear trend toward multi-material or hybrid construction in component manufacture. The key is to use the right material in the right place. Joining technologies are the key to success, because the use of new innovative materials often fails due to a lack of possibilities to produce a reliable joint between dissimilar – but also similar – materials. At Fraunhofer IFAM, a wide range of joining processes is available, which are applied according to the material combination to be joined.

Materials for tribological stress

 

Tribological stresses often occur in conjunction with high temperatures, chemically aggressive media or dynamic loads. This results in the demand for different, usually even contrasting material properties. Powder metallurgy offers excellent potential for the production of tailor-made materials for tribological applications through the choice of a wide variety of alloys as matrix materials, but also through the possibility of incorporating hard and/or lubricating materials.

Materials for energy conversion and storage

 

Thermoelectric generators represent, under ecological and economical aspects especially, a promising possibility to convert waste heat from combustion engines directly into electrical energy. Therefore, processes for the production and processing of modern thermoelectric materials are developed at the institute. The institute also deals with questions of efficient thermal energy storage by characterizing new storage materials and developing high-performance thermal storage units, as well as optimizing heat transfer processes in heating or cooling with the aid of compact single- or two-phase heat exchangers.