Transforming Metal Scrap into High-Performance Alloys with Solid Phase Alloying

Researchers at the Department of Energy's Pacific Northwest National Laboratory (PNNL) have developed an innovative method to directly convert metal scrap into high-performance alloys without the need for traditional melting processes. This breakthrough, detailed in a study published in Nature Communications, shows that scrap aluminum from industrial waste can be transformed into high-quality metal alloys that match the performance of those made from primary aluminum.

The new process, known as solid phase alloying, upcycles aluminum by blending it with copper, zinc, and magnesium to create high-strength aluminum alloys in just minutes, far quicker than the days needed for conventional methods like melting, casting, and extrusion. The team used a patented technique called Shear Assisted Processing and Extrusion (ShAPE) to achieve these results, though the process is adaptable to other solid-phase manufacturing techniques.

"This approach allows us to transform low-cost waste into high-value products in a single step," said Xiao Li, the lead author of the study and a materials scientist at PNNL. The process uses high-speed rotating dies to create friction and heat, which disperses the raw materials into a uniform alloy, producing a product with the same properties as newly manufactured aluminum. This solid-phase method eliminates the need for energy-intensive bulk melting, making it a cost-effective and environmentally friendly way to produce high-quality recycled aluminum.

The new alloy produced through solid phase alloying has been found to be 200 percent stronger than conventional recycled aluminum, with increased ultimate tensile strength. These improvements could lead to longer-lasting, higher-performing products for industries such as automotive, construction, and household appliances. The researchers used mechanical testing and advanced imaging techniques to confirm the enhanced properties, revealing a unique atomic structure in the upcycled materials that contributes to their superior strength.

"Solid phase alloying is not just limited to aluminum, and it could revolutionize the creation of custom metal alloys," said Cindy Powell, PNNL’s chief science and technology officer. "This process opens up possibilities for creating alloys that we haven’t been able to produce before, and could even be applied to 3D printing technologies like wire arc additive manufacturing."

The solid phase alloying technique not only holds the promise of more efficient and sustainable metal recycling but also presents new opportunities for producing advanced alloys for a variety of industrial applications.