Electing High-Entropy Alloy Microstructures
Additive manufacturing has changed the speed and cost of prototyping and production across dozens of industries, but traditional, laser-based 3D-printing techniques used to create metallic alloys can still be limited by hard-to-predict mechanical properties. Lawrence Livermore researchers collaborated with researchers at the University of Massachusetts, Amherst; Oak Ridge National Laboratory; Texas A&M University; the University of Singapore; and the State University of New York at Buffalo to solve this problem.
A study published in the November 6, 2025, issue of Advanced Materials describes how the microstructure of additively manufactured, high-entropy alloys can be controlled by the speed of the laser scan. The team studied the eutectic high-entropy alloy aluminum (Al)–chromium (Cr)–Iron (Fe)–nickel (Ni) called AlCrFe2Ni2, which melts and solidifies at a single temperature, and found that increasing (Image by Daniel Herchek.) laser speed also increased solidification speed. This outcome led to single-phase solidification of the alloy, creating a strong but brittle metal. When the scan was slower, the alloy took longer to cool, giving the atoms inside more time for diffusion and phase separation, which resulted in coupled eutectic growth (simultaneous solidification of two solid phases) and a more flexible alloy.
Fine tuning the properties of metals opens doors for additive manufacturing applications. Livermore staff scientist Thomas Voisin says, “We are now at a place where we can effectively design new materials that take full advantage of additive manufacturing features such as a very rapid cooling rate.”
Contact: Thomas Voisin (925) 423-5235 (voisin2 [at] llnl.gov (voisin2[at]llnl[dot]gov)).
Advancing Hydrocode Material Modeling
In high-energy-density physics, experiments can reach extreme conditions where atomic-scale behavior and macroscale (including hydrodynamic scale) temperature, pressure, and flow effects all converge at once, causing phase changes well outside normal equilibrium limits. To better understand this circumstance, collaborators from Lawrence Livermore and the University of California, Davis, have developed a new framework to process atomic and macroscale simulations concurrently. The research results appeared in the November 21, 2025, issue of Physical Review E.
The team combined a hydrodynamics code from Lawrence Livermore with a molecular dynamics code (large-scale atomic/ molecular massively parallel simulator, or LAMMPS) from Sandia National Laboratories. The two codes run concurrently to calculate in real time how the material’s individual atoms will respond to specific hydrodynamic conditions. The framework requires significant computational power, so researchers have tailored the code to run on the Laboratory’s Tuolumne supercomputer, which mimics the accelerated processing unit architecture of the El Capitan system.
The team’s framework is highly versatile and can be applied to several aspects of study that require a direct bridge between microscopic and macroscopic insights. Livermore scientist Dane Sterbentz says, “This work leads to new applications where nonequilibrium material behavior, including phase transitions (for example, liquid to solid) and chemical reactions, can be concurrently simulated with hydrodynamics using atomistic insights, which is the next stage of our research.”
Contact: Dane Sterbentz (925) 424-4132 (sterbentz2 [at] llnl.gov (sterbentz2[at]llnl[dot]gov)).
Isotherm Models in Electrocatalytic Reactions
Isotherm models have often been overlooked in research on electrically driven chemical reactions. While changes in temperature and pressure propel traditional catalytic reactions, electrochemistry uses voltage to guide the same reactions. Researchers from Lawrence Livermore and the Massachusetts Institute of Technology suggest that adsorption isotherms may be playing a more significant role in these voltage-driven systems than previously thought.
In a December 22, 2025, paper published in Nature Catalysis, the team examined the complexity of electrochemical adsorption isotherm models. The solid–electrolyte interfaces—the boundary between a metal catalyst and the liquid in which it operates— pose the issue of water and salt molecules competing with reactants to stick to the surface, and developing isotherm models that account for this competition is necessary to accurately predict how reactions behave. “This understanding is essential for enabling new electrochemical routes for producing chemicals and materials that are more sustainable, efficient, or secure for the nation,” says Livermore postdoctoral researcher An Chu.
Many studies of electrocatalytic reactions attempt to justify their results without mentioning the potential adsorption of isotherm effects. Chu says, “We aim to shine a light on this important topic, which could turbocharge predictive models of catalysis for emerging technologies.”
Contact: An Chu (925) 423-6298 (chu33 [at] llnl.gov (chu33[at]llnl[dot]gov))
