Observing technology and processes at scales larger than previously possible enables new insights, and grain boundary complexions is one of those.
Driving the news: Researchers at the U.S. Army Research Laboratory and Lehigh University recently developed a new nonstructured metallic alloy that holds its shape under extreme conditions.
How it works: Part of how the new alloy works is by combining copper with a complexion-stabilized nanostructure. Specifically, it forms copper lithium precipitates, stabilized by a tantalum-rich atomic bilayer complexion.
What is a complexion? Defined in this paper, a complexion is interfacial material or strata that is in thermodynamic equilibrium with the abutting phase(s) and has a stable, finite thickness, typically on the order of 0.2–2 nanometers.
Recall from physics (or igneous petrology…whichever is your frame of reference) how materials undergoing phase changes do not change temperature: boiling water is at 212 degrees Fahrenheit (100 degrees Celsius) plus or minus a few degrees, depending on pressure and composition regardless of time or temperature exposure. The energy in that system is spent causing water to undergo a phase change from water to gas.
What complexions do: The best I can deduce is that a complexion improves strength of materials by taking up energy that would have otherwise destabilized the material.
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The complexion then puts that energy toward a phase shift at the boundary layer.
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It stops there, rather than propagating through the rest of the material.
What’s next: The article states, “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.”
Why it matters: The article mentioned this tech could redefine high-temperature materials for aerospace, defense, and industrial applications.
Where geos come in: There’s a lot of space for geoscientists here. We eat complex, multiphase systems with fluctuating pressure, temperature, and chemical conditions for breakfast and have developed a high understanding of such things without being able to directly observe them. Imagine what we could do if we could see the processes!
For more info on the copper breakthrough specifically, read here.