ORNL scientists developed RidgeAlloy, a new aluminum alloy that transforms impure auto-body scrap into strong structural materials. Credit: Shutterstock

A new alloy could turn tomorrow’s vehicle scrap into America’s next manufacturing advantage.

A large influx of aluminum auto body scrap is expected to move through recycling systems over the next ten years. Much of this material contains too many impurities to be reused safely in high-performance automotive components, which significantly reduces its value.

Researchers at the Department of Energy’s (DOE) Oak Ridge National Laboratory (ORNL) have now developed a solution: a new aluminum alloy known as RidgeAlloy. This alloy allows low-grade scrap to be converted into material suitable for producing strong, reliable structural vehicle parts, creating a valuable domestic supply chain.

Aluminum appears on the DOE’s critical materials list because it plays a key role in technologies that generate, transport, store, and conserve energy.

RidgeAlloy is created by melting down post-consumer aluminum scrap and recasting it into a formulation that meets industry standards for strength, ductility, and crash performance. ORNL’s long-standing leadership in aluminum alloy research enabled the team to use a focused design strategy that sped up development.

“The team advanced from a paper concept to a successful, full-scale part demonstration of a new alloy in only 15 months,” said Allen Haynes, director of ORNL’s Light Metals Core Program. “That’s an unheard-of pace of innovation in developing complex structural alloys.”

The challenge of repurposing vehicle scrap aluminum

Aluminum-heavy vehicles began entering the U.S. market around 2015, with Ford’s F-150 among the earliest to be widely produced. By the early 2030s, many of these vehicles will reach the end of their lifespan, generating as much as 350,000 tons of aluminum body sheet scrap each year in North America. Instead of returning as high-value material, much of this scrap is expected to be downgraded into low-grade castings or shipped overseas, representing a lost opportunity for domestic manufacturing.

“You can repurpose post-consumer aluminum into something non-structural like engine blocks,” said Alex Plotkowski, ORNL group leader of Computational Coupled Physics. “But it won’t have the properties needed for higher value, structurally sound body applications.”

This automotive part was manufactured from RidgeAlloy, a new structural alloy developed by researchers at ORNL. It was cast using metals recycled entirely from post-consumer aluminum auto body sheets. Credit: ORNL, U.S. Dept. of Energy

The main issue is contamination. During the shredding process, scrap picks up impurities such as iron from fasteners and mixed components, creating unpredictable and weak chemistries that are unsuitable for commercial structural alloys. As a result, most high-strength vehicle parts continue to rely on primary aluminum, which requires raw ore and a highly energy-intensive production process.

Turning scrap into a domestic supply chain

While primary aluminum is mostly imported, the U.S. has some of the world’s best infrastructure for vehicle shredding and aluminum scrap recovery.

“Using remelted scrap instead of primary aluminum is estimated to result in up to 95% reduction in the energy needed for processing a part,” said Amit Shyam, leader of ORNL’s Alloy Behavior and Design Group.

To make that possible, the team applied world-class scientific tools such as high-throughput computing, which involved more than two million calculations to predict the optimal alloy compositions with targeted properties, as well as materials characterization and neutron diffraction at ORNL’s Spallation Neutron Source, a DOE Office of Science user facility. These tools helped the researchers understand how specific impurities affect alloy behavior. Neutrons are uniquely suited for this kind of research because they can penetrate deep into dense metals without damaging the material, allowing scientists to observe internal structures and atomic-scale changes.

After pinpointing the desired blend through rapid computational predictions and laboratory trials, the new alloy was tested in a real-world environment. PSW Group’s Trialco Aluminum in Chicago supplied recycled aluminum ingots, metal blocks ready for remelting, cast from mixed auto body sheet scrap and tailored to RidgeAlloy’s specifications. The ingots were shipped to Falcon Lakeside Manufacturing in Michigan, where they were successfully cast into automotive parts using high-pressure die-casting.

“The part we chose was medium-sized and moderately complex,” Plotkowski said. “The ultimate goal is to eventually cast larger parts, perhaps even automotive giga-castings, but this is the first step.”

The cast parts confirmed that RidgeAlloy, consisting of aluminum, magnesium, silicon, iron, and manganese, had the combination of properties necessary for structural vehicle castings, even when made from recycled blends with higher iron and silicon content. It delivers strength, corrosion resistance, and ductility, enabling the production of structural castings of underbodies, frame components, and other critical parts from post-consumer aluminum scrap. This breakthrough offers the opportunity to reshape the value equation of how North American auto body sheet scrap is sorted and reused.

From national laboratory to real-world impact

“This team figured out how to take full advantage of a national lab’s world-class suite of capabilities to rapidly fill a huge gap in our understanding of lightweight automotive materials,” Haynes said.

By the early 2030s, RidgeAlloy could enable recycled structural castings at volumes equal to at least half of the annual primary aluminum production in the U.S. This would reduce energy use, cut costs, and strengthen domestic supply chains.

“RidgeAlloy offers the first technology capable of recapturing the value of a fast-approaching and historically massive wave of domestic, high-quality recycled automotive aluminum sheet alloys,” Haynes said. “That’s the big picture supply chain impact our team aimed for.”

There is also potential for future applications in industrial machinery, agricultural equipment, aerospace, mobile power generation equipment, off-road vehicles such as snowmobiles, motorcycles, and marine vehicles, including jet skis.

Funding: This research was supported by DOE’s Office of Energy Efficiency and Renewable Energy, Vehicle Technologies Office Lightweight Metals Core Program.

RidgeAlloy was developed under the Vehicle Technologies Office Lightweight Metals Core Program. The project team from ORNL included Alex Plotkowski, Amit Shyam, Allen Haynes, Sunyong Kwon, Ying Yang, Sumit Bahl, Nick Richter, Severine Cambier, Alice Perrin and Gerry Knapp.

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