Hydrogen solution in high-entropy alloys

Area of Science:

• Materials Science
• Physical Chemistry
• Computational Materials Science

Background:

• High-entropy alloys (HEAs) show promise for hydrogen storage and resistance to hydrogen embrittlement.
• Hydrogen solution behavior in HEAs is crucial for these properties but complex due to diverse atomic environments.
• Calculating hydrogen solution energy in HEAs is challenging.

Purpose of the Study:

• To elucidate the origins of varying hydrogen solution energies in HEAs.
• To establish a generalized model for predicting hydrogen solution energy and distribution.
• To provide insights into hydrogen-induced microstructural evolution in HEAs.

Main Methods:

• Combined semi-empirical atom potential and first-principles calculations.
• Investigated hydrogen interaction with host atoms in FeCrCoNi, NbMoTaW, and FeCuCrMnMo HEAs.
• Analyzed chemical and elastic interaction contributions to hydrogen solution energy.

Main Results:

• Identified a linear relationship between elastic interaction and volume expansion upon hydrogen insertion.
• Observed a non-linear correlation between chemical interaction and interstitial polyhedron volume.
• Developed a universal model to generalize hydrogen solution energy in HEAs.

Conclusions:

• The established model accurately predicts hydrogen distribution in HEAs.
• Understanding chemical and elastic interactions is key to HEA design for hydrogen applications.
• The model offers insights into microstructural changes driven by hydrogen in HEAs.