Lightweight Structures and Excellent Energy Absorption Using Highly Porous Materials
Fraunhofer IFAM has facilities for variety of powder-metallurgical and casting processes for manufacturing highly porous materials (metal foams).
Depending on the area of application, open and closed pore metal foams made of different materials (aluminum, zinc, lead, steel, etc.) can be manufactured and customized to requirements.
Besides manufacturing these materials, viable production technologies and complete components and sub-assemblies are developed. Composite systems – comprising aluminum foam and conventional sheets or sections made of steel or aluminum – have promising applications for lightweight construction.
Energy-absorbing and noise-damping structures for car manufacture and very rigid, 3-dimensional molded parts also present potentially innovative applications for metal foams.
Application fields for porous metals
Porous metals are characterized by low densities, high specific stiffness, good energy absorption capability and good damping properties. Therefore, application fields can be found in lightweight design, crash energy absorption and vibration damping. Open porous metals feature large specific surfaces, good mechanical and thermal stability and high thermal conductivities. They can be used as support material for active materials like PCM, MOF or zeolites. The complex 3D-structure of the foams lead to intensive contact and transfer conditions to fluids and to improved heat transfer or phase change processes.
The trademark for metal foams: FOAMINAL®
The best known process for manufacturing closed cell metal foams is the so-called powder-metallurgical Fraunhofer IFAM process. Here, commercially available metal powders are mixed with small amounts of a powder foaming agent and compressed into a compact molding. On subsequent heating the material expands, producing a highly porous, closed cell structure.
The process was originally developed for aluminum and its alloys but has in the meantime been transferred to various other metals (zinc, lead, bronze, titanium, steel, etc.).
Aluminum foams made using the Fraunhofer IFAM process bear the trademark FOAMINAL®. A variant of the Fraunhofer IFAM process is being used to manufacture metal foam components from many small-volume metal foam elements. These foam elements can be adapted to the requirements of the component (shape/geometry, density, alloy). They can either be used as loose fill (unbound), precompacted (micro-mechanical adhesion), or material-fit (bonded, sintered, soldered/brazed). These process variants are termed Advanced Pore Morphology (APM).