The science behind high-entropy alloys
Why mixing several metals in near-equal amounts creates materials with unusual combinations of properties, and how Trumet designs them.
A different way to build an alloy
For most of history, alloys have been made by taking one main metal, such as iron, aluminium or nickel, and adding small amounts of others. Steel is mostly iron. Aluminium alloys are mostly aluminium.
High-entropy alloys, first described in 2004, take a different approach. They combine five or more principal elements, each typically between 5 and 35 atomic percent. The large number of ways those atoms can arrange themselves raises the alloy's configurational entropy, which can stabilise simple crystal structures instead of brittle compounds.
The result is a vast, mostly unexplored family of materials. Some have shown exceptional strength, toughness at low temperatures, wear resistance or corrosion resistance.
Four effects researchers look for
High entropy
Many elements mixing randomly lowers free energy and can favour a single solid-solution phase.
Lattice distortion
Atoms of different sizes strain the crystal lattice, which hinders dislocation movement and can raise strength.
Sluggish diffusion
Atoms move more slowly through the mixed lattice, which can help the alloy remain stable at high temperature.
Cocktail effect
The combined behaviour of the mix can exceed what any single element would suggest.
Why design needs software
The opportunity is also the problem. Even with just five fixed elements, stepping each by 1% between 5 and 35 at.% gives 553,401 distinct compositions. Choose the five from a broader palette of metals and the number grows by orders of magnitude.
No laboratory can make and test them all. Trumet's approach combines established materials science rules, computational models and multi-criteria ranking to decide which few are worth making, then confirms the prediction through fabrication and characterization.
How the platform worksTrumet's research
Our research focuses on multi-criteria alloy design, the development of CuAlFeMnNi, and applications in aerospace, defense, marine and additive manufacturing.