How Atomic Bonding Plays the Hardness Behavior in the Al-Co-Cr-Cu-Fe-Ni High Entropy Family

Area of Science:

• Materials Science
• Metallurgy
• Solid-State Physics

Background:

• Compositionally complex alloys (CCAs) offer tunable properties for advanced applications.
• Understanding individual element contributions in multi-component systems is crucial for alloy design.

Purpose of the Study:

• To systematically analyze the influence of each alloying element on the properties of a face-centered cubic (FCC) Al-Co-Cr-Cu-Fe-Ni alloy.
• To establish structure-property relationships, specifically linking local atomic distortions to microhardness.

Main Methods:

• Experimental techniques: X-ray absorption spectroscopy, X-ray diffraction, transmission electron microscopy.
• Computational methods: First-principles hybrid Monte Carlo/molecular dynamics simulations.
• Analysis of chemical short-range order, bond lengths, and electronic structure.

Main Results:

• Quantified the contribution of individual elements to the solid solution in the senary alloy and its suballoys.
• Determined chemical short-range order and bond length distributions experimentally and computationally.
• Established a correlation between electronic structure, local atomic distortions, and microhardness.

Conclusions:

• Local atomic distortions significantly influence the microhardness of the alloy system.
• A linear regression model effectively predicts hardness based on local lattice distortions.
• This work provides a framework for designing high-performance CCAs by controlling atomic-level features.