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.
This and other innovative alloys will continue to be studied in Lehigh’s newly outfitted high-tech research labs, the Nanoalloy Lab and Nanoceramics Lab, which include high-pressure torsion systems, nanoindentation equipment and specialized high-temperature furnaces.
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 pioneered by the Lehigh researchers. 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.
Patent, Funding and Future Work
A project such as this takes years of careful work and collaboration, said Christopher Marvel ’12 ’16 Ph.D., an author of the paper and professor of mechanical engineering at Louisiana State University.
“Lehigh has such a strong reputation for electron microscopy, and that is what interested the ARL in working with us on this material. It was our microscopy that was really key to understanding the material,” said Marvel, who helped lead that portion of the research over a six-year period. “The Lehigh faculty have worked on many high-level research projects over the years, and they’ve all taught me different things that I apply now as an academic.”
The ARL 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 work is just one of many collaborations between Lehigh and ARL which have resulted in significant discoveries, papers in high-profile publications, award-winning poster submissions and the placement of Lehigh students in prestigious fellowships.
Alum Joshua Smeltzer ’17 ’23 Ph.D., now a design engineer at Honeywell, also contributed to the research, performing advanced microstructural characterization of the superalloy using Lehigh's Atomic Resolution Microscope (ARM).
“Lehigh's ARM, a state-of-the-art electron microscope, is a unique instrument that enables scientists to analyze materials on the atomic scale,” Smeltzer said. “In this work, the ARM was used to image the superalloy at the nano- and atomic-scales to provide a mechanistic explanation for the alloy's exceptional performance.”
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.”
Story by Dan Armstrong
Lehigh has been named an R1 research university by the Carnegie Classification of Institutions of Higher Education. Universities with this designation conduct the highest level of research activity within the Carnegie Classification. Lehigh is the only university in the Lehigh Valley to have this designation, and one of seven in Pennsylvania. Learn more.
