What’s at the leading edge of research in the simulation of high entropy alloys?

What is it about?

Alloys are metals made up of two or more elements and have better properties than the elements alone. High entropy alloys (HEAs) are alloys made of four, five, or more elements, mixed in nearly equal amounts. HEAs have much better mechanical properties than the elements that make them up. Predicting the mechanical properties of HEA using atomistic simulations can help advance research in the field. Atomistic simulations of HEAs are very complex and take a lot of time, as well as computing power. In some cases, they even need a lot of human effort. But research on the atomistic simulations of HEAs is progressing rapidly. This paper condenses three recent and significant improvements in the field. The first is the use of tools called machine learning potentials (MLPs). The second is the improved knowledge of “short-range order (SRO)” and its influence on material properties. The final topic is the use of defects, anomalies in the crystal structure surrounding a substituted element.

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Photo by Laura Ockel on Unsplash

Photo by Laura Ockel on Unsplash

Why is it important?

HEAs can only be formed when the atoms are arranged in a particular way. Atomistic simulations are an important, quick, and inexpensive way of predicting HEAs. This paper highlights how MLPs can boost the accuracy of thermodynamic calculations in atomistic simulations. It then describes how analyzing SRO can improve predictions of crystal structure. Analyzing SRO can also help better predict the larger physical properties of HEAs. Finally, the paper touches upon the deliberate use of defects in HEAs. The study of interstitials (the spaces between elements in a crystal structure) and surfaces can help greatly expand the applications of HEAs. It can even help build HEAs with more enhanced physical properties. KEY TAKEAWAY: The properties of HEAs depend on its composition of atoms and how its atoms are arranged. The paper looks at recent research on the atomistic simulations of HEAs. It focuses on three recent and important topics that are likely to guide future research in the field.