In the lab, scrap-based aluminum foam shows comparable densities

Processed aluminum chips can serve as the starting point for a material usually made from carefully produced alloy powder. Researchers at Fraunhofer IWU ground and classified clean, single-alloy chips, then converted the resulting powder-like feedstock into foamable semifinished products. The aluminum foams produced in the laboratory reached structures and densities comparable to conventionally manufactured foams.

That matters because aluminum foam combines low density with energy absorption and damping properties, making it useful for automotive engineering, machine structures, construction and lightweight energy systems. Until now, production has relied primarily on aluminum alloy powders, whose manufacture is relatively complex and costly. Replacing some or all of that virgin powder with processed chips offers a route to keep production scrap inside the material cycle.

Fraunhofer IWU also tested larger aluminum residues, including foils, coils and wheel-rim material. Cutting, crushing, grinding and sieving turned them into particles with defined sizes suitable for foam production. End-of-life aluminum foam components could, in principle, also return to the cycle through dedicated comminution, sorting and material-specific reprocessing.

The team is not limiting recycling to remelting. Its solid-state recycling approaches retain much of the existing material structure, which the researchers say can save additional energy while minimizing material losses. The environmental case rests on a clear difference in production: secondary aluminum requires far less energy than primary aluminum, with potential reductions in material costs and CO₂ emissions.

This could give manufacturers in automotive, mechanical engineering and rail transportation another way to use production scrap in lightweight material. The technology is not yet industrially established. Fraunhofer IWU’s next steps are to manage fluctuations in scrap quality, measure the full life-cycle impact and prepare the process for broader adoption.