New alloy families made from recycled aluminum for sustainability and conservation of resources

• Applicant: Dr.-Ing. Hanka Becker
• Subject Area: Metallurgical, Thermal and Thermomechanical Treatment of Materials
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 524220218

The need to deal with recycled, secondary materials is constantly increasing. In terms of circular economy, sustainability and resource conservation, the use of recycled, secondary aluminum alloys or closed-loop aluminum alloys offers comparatively particularly large potential. The production of primary aluminum accounts for 3% of total greenhouse gas emissions (15% of emissions in the industrial sector). It requires 1% of global energy production. The energy consumption for processing circular Al alloys is only 5% compared to primary aluminum. The effect of using closed-loop Al alloys to reduce emissions is enormous. It is estimated that the amount of recycled Al will exceed the primary aluminum production in a few years. In the recycling process, impurity and accompanying elements such as Fe, Cu, Ti, V, Cr, Mn, Co, Ni and Zn accumulate beyond the tolerance limits. Due to the formation of intermetallic phases, these elements have a predominantly negative effect on the properties in the entire range of applications of aluminum. The causal removal of the impurity and accompanying elements is associated with an unacceptable high energy consumption or loss of material, or only a partial reduction is achievable. Currently, high-energy pure primary aluminum is added for dilution in order to comply with compositional tolerances of the alloys. However, it is expected that there will be limits for the use of primary aluminum in new products in the future. Research into how to deal with the impurities and accompanying elements that are unavoidably introduced during recycling while maintaining the quality for the use of closed-loop aluminum alloys is of exceptional interest for the environment and the economy. The proposed project has the visionary goal of laying fundamental scientific findings in order to create new families of closed-loop aluminum alloys whose outstanding properties are comparable to or better than those of classic alloys and make economic sense, as well as meeting the sustainability requirement and not degrading in further circulatory cycles. It should thus be possible to integrate every recycled Al component as a closed-loop Al alloy. Here, the intermetallic phases are specifically adjusted by new refiners so that their presence in the microstructure can be tolerated or even be used without any disadvantages. Research into the production and effect of new tailor-made active-reactive refiners and additional surface-active elements using extracted and processed alloy-specific intermetallic particles with the impurity and accompanying elements themselves on the formation of the intermetallic phases provides the key for the appropriate use of those unavoidable impurity - and accompanying elements.

• DFG Programme: Independent Junior Research Groups