Breakthrough research redefining materials science through atomic-level engineering
In a world where technological progress is often measured in months rather than years, one fundamental field—materials science—had remained relatively unchanged for a century. Superalloys, materials capable of withstanding extreme temperatures in jet engines and power plants, have been based on nickel, cobalt, and iron for over 100 years. Copper, while possessing superior electrical conductivity, was always too weak for high-temperature structural use. But today, in the laboratories of Lehigh University, this barrier has collapsed.
This work, recognized as one of the 10 major scientific breakthroughs of 2025 in the physical sciences by the Falling Walls Foundation, opens a new era in nanotechnology—an era in which material weaknesses become their greatest strengths 1 .
Manipulating matter at the atomic level to create materials with unprecedented properties.
Recognized as a top scientific breakthrough by the Falling Walls Foundation in 2025.
Throughout most of materials science history, grain boundaries—the areas where crystals within a material meet—were considered its Achilles' heel. This is where the material often begins to break down under stress or high temperature. Lehigh researchers, however, have discovered that these interfaces can not only be controlled but purposefully engineered.
They learned to manipulate complexions—phase-like structures that exist at atomic interfaces between grains in a material 1 . Imagine the mortar that holds bricks in a wall. Lehigh engineers have learned not just to choose the best mortar, but to create a new type of mortar that makes the wall not just strong, but practically eternal.
Using this strategy, Professor Martin Harmer's team developed the world's first copper superalloy (Cu–Ta–Li) 1 . This is a material that combines the high strength and stability traditionally associated with nickel superalloys with the exceptional thermal and electrical conductivity of copper.
The secret to its stability lies in nanoscale Cu₃Li precipitates that are stabilized by tantalum-rich complexions. These tantalum bilayer complexions—structures just two atoms thick—form a protective barrier around the precipitates, preventing their growth and coalescence even at temperatures approaching copper's melting point 1 .
"These tantalum bilayer complexions make the alloy so stable that it can be held near its melting point for over a year without loss of nanostructure," explains Professor Harmer. "For copper, this is unprecedented." 1
While one team was working on complexions, another group led by Professor Fadi Abdeljawad was making discoveries in even tinier regions—triple junctions. These are the corners where three nanocrystals meet 2 .
Their research, published in Nano Letters, showed that when platinum is doped with gold, gold atoms preferentially occupy positions at these triple junctions. This "chemical segregation" effectively locks the grain boundaries in place, preventing their growth and preserving the material's strength at high temperatures 2 . This discovery provides scientists with a new tool for designing stable nanocrystalline alloys by purposefully selecting elements that will stabilize the material at these key points.
To appreciate the magnitude of this achievement, it's worth examining in detail how this revolutionary material was created.
Researchers began with cryogenic high-energy milling. At this stage, powders of copper, tantalum, and lithium undergo intense mechanical alloying at very low temperatures. This creates a metastable solid solution—a homogeneous mixture of elements at the atomic level that would not exist under normal conditions 1 .
The material then undergoes controlled thermal treatment. Upon heating, tantalum atoms, driven by thermodynamic forces, migrate to the interfaces of copper and lithium nanoparticles. There they self-organize, forming the very protective bilayer complexions that are key to the alloy's stability 1 .
Mechanical alloying at ultra-low temperatures creates metastable solid solutions.
Controlled heating enables self-organization of atomic structures.
Advanced microscopy confirms formation of stabilizing complexions.
The experimental results exceeded all expectations. Unlike conventional copper alloys, which quickly lose strength at high temperatures, the new material demonstrated exceptional stability.
| Material | Maximum Operating Temperature (°C) | Nanostructure Preservation at 800°C | Key Stabilizing Mechanism |
|---|---|---|---|
| Traditional Copper Alloy | ~400 | Minutes/Hours | Solid Solution Strengthening |
| Nanocrystalline Copper | ~500 | Hours | Grain Boundary Strengthening |
| Cu–Ta–Li Superalloy (Lehigh) | >900 (near melting point) | Over a year | Tantalum Bilayer Complexions |
This preservation of nanostructure is directly related to mechanical properties. The material demonstrates exceptional resistance to creep—the tendency of a material to slowly deform under constant load at high temperatures.
The scientific significance of this achievement is profound. It does not merely represent a new alloy, but validates an entirely new material design strategy at the atomic level. It proves that grain boundaries and interfaces, long considered defects, can be transformed into a material's greatest asset 1 .
The success of research at Lehigh is driven not only by brilliant ideas but also by access to cutting-edge tools and materials.
| Reagent/Tool | Function in Research | Lehigh Case Study |
|---|---|---|
| Tantalum (Ta) and Lithium (Li) | Alloying elements forming nano-precipitates Cu₃Li and stabilizing complexions. | Key components for creating stable nanostructure in Cu-alloy 1 . |
| Cryogenic High-Energy Mill | Mechanical alloying of elements at ultra-low temperatures to create metastable solid solution. | Used to create initial homogeneous Cu–Ta–Li alloy before thermal treatment 1 . |
| Transmission Electron Microscopy (TEM) | Direct observation and analysis of atomic structures, complexions and grain boundaries. | Lehigh has one of the world's best academic microscopy centers, allowing visualization of tantalum bilayer complexions 1 7 . |
| Scanning Tunneling Microscope | Manipulation of individual atoms and molecules. | Used for fundamental research of interactions at the atomic level 3 . |
| X-ray Diffraction (XRD) | Determination of crystal structure, particle size and internal stresses in nanomaterials. | Standard method for characterizing nanostructure of created materials . |
| Computational Modeling | Predicting atomic behavior and designing new materials before their synthesis in the laboratory. | Professor Abdeljawad uses large-scale computations to predict effects such as segregation at triple junctions 2 . |
Nanotechnology research at Lehigh University is not merely an academic exercise. This is work that could fundamentally transform entire industries. Professor Harmer sees his work paving the way for new classes of thermally stable, high-performance nanocrystalline alloys—materials that could contribute to improved energy efficiency, enhanced turbine performance, and more sustainable forms of transportation 1 .
Discoveries like the stabilization of triple junctions offer a new set of rules for designing the next generation of materials for aerospace and energy industries 2 . These breakthroughs have been made possible by the culture of collaboration that defines Lehigh's approach—collaboration between experimentalists and theorists, between universities and national laboratories.