First principles-based design of lightweight high entropy alloys

Area of Science:

• Materials Science
• Computational Materials Design
• Alloy Development

Background:

• Lightweight high entropy alloys (HEAs) are increasingly important for structural applications.
• Existing lightweight alloys often have limitations in performance or stability.
• There is a need for advanced materials with superior properties.

Purpose of the Study:

• To design novel lightweight HEAs with a single solid-solution phase.
• To identify HEA compositions with optimal combinations of low density, high stability, and excellent mechanical properties.
• To provide guidance for the experimental synthesis of new lightweight HEAs.

Main Methods:

• Utilized a first-principles-based high-throughput computational approach.
• Systematically explored compositional spaces for three quinary HEA families (AlBeMgTiLi, AlBeMgTiSi, AlBeMgTiCu).
• Applied design criteria including stability, mass density, elastic modulus, specific stiffness, and Pugh's ratio.

Main Results:

• Identified promising HEA compositions with negative formation energy, low density, and high specific Young's modulus.
• The most stable composition, Al0.31Be0.15Mg0.14Ti0.05Si0.35, demonstrated superior energetic stability and outperformed 7075 Al alloy.
• Designed HEAs exhibit enhanced stability, lower density, and higher stiffness compared to current aluminum alloys, albeit with slightly reduced ductility.

Conclusions:

• The developed computational methodology effectively guides the design of lightweight HEAs.
• The identified HEA compositions represent promising candidates for next-generation lightweight structural materials.
• These findings facilitate the experimental realization of advanced, high-performance lightweight alloys.