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Nanostructured copper alloy rivals superalloys in strength and stability

Researchers from the U.S. Army Research Laboratory (ARL) and Lehigh University have developed a nanostructured copper alloy that could redefine high-temperature materials for aerospace, defense, and industrial applications.

Their findings, in the journal Science, introduce a Cu-Ta-Li (copper-tantalum-lithium) alloy with exceptional thermal stability and mechanical strength, making it one of the most resilient copper-based materials ever created.

"This is cutting-edge science, developing a new material that uniquely combines copper's excellent conductivity with strength and durability on the scale of nickel-based superalloys," said Martin Harmer, the Alcoa Foundation Professor Emeritus of Materials Science and Engineering at Lehigh University and a co-author of the study. "It provides industry and the military with the foundation to create new materials for hypersonics and high-performance turbine engines."

The ARL and Lehigh researchers collaborated with scientists from Arizona State University and Louisiana State University to develop the alloy, which can withstand extreme heat without significant degradation.

Combining copper with a complexion-stabilized nanostructure

The breakthrough comes from the formation of Cu₃Li precipitates, stabilized by a Ta-rich atomic bilayer complexion, a concept the . Unlike typical grain boundaries that migrate over time at high temperatures, this complexion acts as a structural stabilizer, maintaining the nanocrystalline structure, preventing grain growth, and dramatically improving high-temperature performance.

The alloy holds its shape under extreme, long-term thermal exposure and mechanical stress, resisting deformation even near its melting point, noted Patrick Cantwell, a research scientist at Lehigh University and co-author of the study.

By merging the high-temperature resilience of nickel-based superalloys with copper—which is known for exceptional conductivity—the material paves the way for next-generation applications, including heat exchangers, advanced propulsion systems, and thermal management solutions for cutting-edge missile and hypersonic technologies.

A new class of high-performance materials

This new Cu-Ta-Li alloy offers a balance of properties not found in existing materials:

• Nickel-based superalloys (used in jet engines) are extremely strong but lack the high thermal conductivity of copper alloys.
• Tungsten-based alloys are highly heat-resistant but dense and difficult to manufacture.
• This Cu-Ta-Li alloy combines copper's exceptional heat and electrical conductivity while remaining strong and stable at extreme temperatures.
• While not a direct replacement for traditional superalloys in ultra-high temperature applications, it has the potential to complement them in next-generation engineering solutions.

How the researchers made and tested it

The team synthesized the alloy using powder metallurgy and high-energy cryogenic milling, ensuring a fine-scale nanostructure. They then subjected it to:

• 10,000 hours (over a year) of annealing at 800°C, testing its long-term stability.
• Advanced microscopy techniques, revealing the Cu₃Li precipitate structure.
• Creep resistance experiments, confirming its durability under extreme conditions.
• Computational modeling using density functional theory (DFT), which validated the stabilizing role of the Ta bilayer complexion.

The U.S. Army Research Laboratory was awarded a U.S. patent (US 11,975,385 B2) for the alloy, highlighting its strategic significance, particularly in defense applications like military heat exchangers, propulsion systems, and hypersonic vehicles.

The scientists say further research will include direct measurements of the alloy's thermal conductivity compared to nickel-based alternatives, work to ready it for potential applications, and the development of other high-temperature alloys following a similar design strategy.

"This project is a great example of how federal investment in fundamental science drives American leadership in materials technology," Harmer said. "Scientific discoveries such as this are key to strengthening national security and fueling industrial innovation."