image: Superalloy research conducted by Lehigh University’s Martin Harmer, the Alcoa Foundation Professor Emeritus of Materials Science and Engineering, has been honored by the Falling Walls Foundation as a top 10 scientific breakthrough for 2025.
Credit: Lehigh University
The Falling Walls Foundation, one of the world’s most respected platforms for scientific innovation, has named Lehigh University's Martin Harmer among the Top 10 Breakthroughs of the Year 2025 in Physical Sciences for his pioneering work on copper-based superalloys. The honor places Harmer, Lehigh's Alcoa Foundation Professor Emeritus of Materials Science and Engineering and Director of the Nano|Human Interfaces Presidential Research Initiative, in a select circle of researchers whose work is reshaping our understanding of the physical world.
Falling Walls, based in Berlin, Germany, takes its name from the fall of the Berlin Wall in 1989—a symbol of overcoming barriers. Each year, the organization recognizes breakthroughs across disciplines that “break walls” in science and society. Inclusion on its Top 10 list is considered one of the most prestigious endorsements a scientist can receive, signifying global peer recognition at the highest level. Harmer and associated team of collaborators’ breakthrough is entitled, “Breaking the Wall of 100 Years of Superalloys.”
“This is a profoundly humbling honor,” says Harmer. “Falling Walls highlights not only the science but the human aspiration to push boundaries. To be recognized alongside such extraordinary work from around the world is a privilege. This research was a true team effort of world-class collaborators.”
Breaking the wall of unstable nanocrystalline materials
Harmer’s recognition stems from a major advance in the design of superalloys—materials engineered to maintain exceptional strength, stability, and performance at extreme temperatures. The work of Harmer and his team of collaborators breaks a century-old limitation in superalloys, which currently relies on single crystal Ni-based alloys for structural integrity at the highest temperatures. The researchers developed a breakthrough Cu-based nanocrystalline material, which offers exceptional stability and structural integrity at high temperatures.
The breakthrough was inspired in part by physicist Richard Feynman’s 1959 lecture, "There's Plenty of Room at the Bottom," which envisioned building materials atom by atom. For Harmer and his collaborators—including scientists at the Army Research Laboratory, Louisiana State University, and Arizona State University—the key lay in manipulating complexions, phase-like structures that exist at the atomic interfaces between grains in a material.
Through precision electron microscopy and years of systematic study, the team learned to engineer complexions that could "lock in" nanoscale structures, preventing the grain growth and creep deformation that typically doom nanocrystalline materials in high-temperature environments.
The world’s first copper-based superalloy
Traditionally, superalloys are made from nickel, cobalt, or iron—metals capable of withstanding extreme conditions but lacking copper’s exceptional electrical and thermal conductivity. Copper alloys have never been viable for high-temperature structural uses because they rapidly lose strength near their melting point.
Harmer and team changed that. They developed a new Cu–Ta–Li superalloy in which tantalum-rich complexions stabilize coherent nanoscale Cu₃Li precipitates. Using cryogenic high-energy milling, they created a metastable solid solution of copper, tantalum, and lithium. Upon heat treatment, tantalum atoms formed bilayer complexions—two-atom-thick structures—around the precipitates, protecting them from coarsening even under extreme heat.
“These tantalum bilayer complexions make the alloy so stable that it can be held near its melting point for over a year without losing its nanostructure,” Harmer explains. “It’s unprecedented for copper.”
This atomic-level engineering mirrors the precipitate structures in nickel superalloys—key to their durability—but in a material that offers dramatically better thermal and electrical conductivity. The result is a copper-based nanocrystalline superalloy that resists creep and coarsening, potentially transforming applications in high-performance electronics, power generation, and advanced transportation.
Impact beyond the lab
Harmer envisions this work opening the door to entirely new classes of thermally stable, high-performance nanocrystalline alloys—materials that could contribute to energy efficiency, improved turbine performance, and more sustainable forms of transportation.
The scientific significance is equally profound. By showing that grain boundaries and interfaces—often regarded as flaws—can be purposefully engineered, Harmer’s research reframes a fundamental assumption in materials science.
“This is a new design strategy for materials at the atomic level,” Harmer says. “It’s about turning what was once seen as a weakness into the material’s greatest strength.”
About the Falling Walls Foundation
Founded in 2009, the Falling Walls Foundation brings together leaders from science, business, politics, and the arts to share the latest research and innovation. Its annual Science Breakthroughs of the Year list is the product of an extensive nomination and evaluation process, culminating in presentations at the Falling Walls Science Summit in Berlin each November.
For scientists, being named a Falling Walls Top 10 Breakthrough carries the kind of professional prestige that can shape careers, open doors to international collaborations, and amplify the societal impact of their work.
“To be included on this list means your peers see your work as changing the conversation in your field,” says Harmer. “It’s a reminder that even the most fundamental research has the potential to change the world.”
About Martin Harmer
Martin Harmer, Ph.D., D.Sc. is the Alcoa Foundation Professor Emeritus of Materials Science and Director of the Nano|Human Interfaces Presidential Research Initiative at Lehigh University. His career has been defined by groundbreaking discoveries at the intersection of nanotechnology and materials engineering, most notably the identification and characterization of complexions—phase-like states at grain boundaries that can be engineered to dramatically alter a material’s properties.
Harmer’s research has solved long-standing mysteries in materials science, including abnormal grain growth and liquid metal embrittlement. His awards and honors include support from the W.M. Keck Foundation, the Alexander von Humboldt Foundation, and the National Science Foundation Presidential Award.
Beyond his research, Harmer is recognized for his mentorship and international collaborations, fostering connections that have advanced the field and shaped the careers of emerging scientists. His work continues to influence the design of advanced materials for applications from aerospace to energy.
More about his research can be found at https://nhi.lehigh.edu/martin-harmer.