A canonical stability-elasticity relationship verified for one million face-centred-cubic structures

Area of Science:

• Materials Science
• Computational Materials Science
• Condensed Matter Physics

Background:

• Thermodynamically stable or metastable phases correspond to minima in a material's energy landscape.
• The depth and steepness of these energy minima dictate thermodynamic stability and elastic properties, respectively.
• Alloying has long been used to tune material properties, but systematic exploration of metastable configurations is a recent advancement.

Purpose of the Study:

• To investigate and establish rules governing the elastic properties of face-centered-cubic (FCC) intermetallic compounds.
• To explore the relationship between thermodynamic stability and elastic properties in metastable alloy configurations.
• To simplify the search for new materials with optimized properties within vast configuration spaces.

Main Methods:

• Utilized first-principles calculations to study four binary alloy systems.
• Analyzed a large subset of the FCC configuration space.
• Applied statistical correlation analysis (Spearman correlation) and linear regression.

Main Results:

• Identified a consistent negative correlation between stiffness and heat of formation across various concentrations in FCC intermetallic compounds.
• Demonstrated that the averaged stiffness of metastable configurations decays linearly with their proximity to the ground-state line (zero Kelvin phase diagram).
• Established predictable relationships for elastic properties within the studied alloy systems.

Conclusions:

• The elastic properties of FCC intermetallic compounds follow discernible rules, linking thermodynamic stability and stiffness.
• These findings provide a simplified approach to materials design by predicting properties from energy landscape characteristics.
• The established correlations can guide the efficient search for novel materials with desired mechanical characteristics.