Scientists turn scrap car aluminum into high-performance metal for new vehicles

Researchers at the Department of Energy’s (DOE) Oak Ridge National Laboratory (ORNL) are working to change that. The team created a new aluminum alloy called RidgeAlloy that can convert low value recycled aluminum into a reliable source of material for manufacturing structural automotive parts in the United States.

Aluminum appears on DOE’s critical materials list because it plays an important role in many energy technologies, including systems used to generate, transmit, store and conserve energy.

RidgeAlloy is made by remelting aluminum recovered from used products and recasting it into a new alloy designed to meet the strength, ductility and crash safety requirements of structural vehicle components. ORNL researchers developed a targeted alloy design approach that speeds up the development of new materials.

“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 Growing Challenge of Recycled Automotive Aluminum

Vehicles that rely heavily on aluminum began appearing in the U.S. market around 2015, including the Ford F-150 truck series, one of the first aluminum intensive models produced at large scale. Many of those vehicles are expected to reach the end of their usable life by the early 2030s. When that happens, recycling systems could receive as much as 350,000 tons of aluminum body sheet scrap every year in North America.

A large portion of this material may end up being used in lower value cast products or exported abroad. That represents a missed opportunity to reuse the metal as a domestic source of high quality aluminum.

“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.”

The main challenge comes from contamination introduced during the vehicle shredding process. Small amounts of iron from parts such as rivets and other fasteners mix into the recycled metal. These impurities make the chemical composition unpredictable and reduce performance, which prevents the material from meeting the strict standards required for structural automotive alloys.

Because of this, most lightweight vehicle parts are still made from primary aluminum produced from mined ore. That process requires significant amounts of energy.

Turning Scrap Aluminum Into a Domestic Resource

Although the United States imports most of its primary aluminum, the country has a well developed network for shredding vehicles and recovering aluminum scrap.

“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 create RidgeAlloy, researchers used advanced scientific tools to design the alloy composition. High throughput computing was used to perform more than two million calculations that predicted which combinations of elements would deliver the desired mechanical properties. The team also conducted detailed materials analysis and neutron diffraction experiments at ORNL’s Spallation Neutron Source, a DOE Office of Science user facility.

These experiments helped scientists understand how different impurities influence alloy performance. Neutrons are especially useful for studying metals because they can pass through dense materials without causing damage, allowing researchers to observe internal structures and changes at the atomic scale.

From Computer Models to Real Automotive Parts

After identifying the optimal alloy formula through simulations and laboratory testing, the researchers evaluated RidgeAlloy under real manufacturing conditions.

PSW Group’s Trialco Aluminum in Chicago produced recycled aluminum ingots made from mixed automotive body sheet scrap that matched the RidgeAlloy design. These ingots were then sent to Falcon Lakeside Manufacturing in Michigan, where they were melted and cast into automotive components 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.”

Testing confirmed that RidgeAlloy contains the combination of aluminum, magnesium, silicon, iron and manganese needed for structural vehicle castings, even when the recycled metal includes higher levels of iron and silicon. The material provides the strength, corrosion resistance and ductility required for demanding applications such as vehicle underbodies, frame elements and other key structural parts.

This capability could significantly change how automotive aluminum scrap is sorted, valued and reused across North America.

Expanding the Impact Beyond the Lab

“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 aluminum castings at volumes equal to at least half of current annual primary aluminum production in the United States. That shift could lower energy consumption, reduce manufacturing 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.”

The technology may also find uses beyond passenger vehicles. Potential applications include industrial equipment, agricultural machinery, aerospace systems, mobile power generation equipment, off road vehicles such as snowmobiles and motorcycles, and marine vehicles including jet skis.

The ORNL research team included Alex Plotkowski, Amit Shyam, Allen Haynes, Sunyong Kwon, Ying Yang, Sumit Bahl, Nick Richter, Severine Cambier, Alice Perrin and Gerry Knapp. The project was supported by DOE’s Office of Energy Efficiency and Renewable Energy, Vehicle Technologies Office Lightweight Metals Core Program.