Presentation: 2025 ND EPSCoR Annual conference 

October 21, 2025, NDSU Memorial Union, Fargo, North Dakota

Computational Investigation of Thermodynamic Stability in Novel High Entropy MAB Phases Based on the Cr₄AlB₄ Structure

High-Entropy Alloys (HEAs) signify a new trend in materials designing owing to their unique properties, which reflect from the inherent configurational entropy that stabilizes their solid solution phases. In this study, we aim to explore the application of the HEA concept to the MAB-phase crystal structures. Our target material is Cr₄AlB₄, a promising MAB-phase material that exhibits excellent mechanical strength, thermal stability, and electrical conductivity. However, its properties can be further optimized by substituting Cr atoms with transition metals to examine the thermodynamic stability of several new multi-element MAB-phases using first principles calculations based on Density Functional Theory (DFT). By computing the 0K "Energy Above Hull" (ΔHhull), the stability of every high-entropy composition, for multi-element systems containing Cr, Ti, W, Mn, Mo, and Fe, was thoroughly assessed. This was accomplished by contrasting each HEA's DFT calculated formation energy with the convex hull of every known competing phase. According to our findings, certain elemental combinations result in thermodynamically stable or nearly stable phases. Notably, stable ground states are predicted for the compositions like Cr3WAlB4 (ΔHhull=+0.003eV/atom) and Cr3MnAlB4 (ΔHhull=-0.0001eV/atom). Moreover, we examined how configurational entropy affected phase stability at high temperatures. We show that several metastable compositions, including Cr1.33Mo1.33W1.33AlB4, are expected to become thermodynamically stable at experimentally relevant synthesis temperatures by computing the Gibbs Energy Above the Hull. These results offer essential theoretical direction for the focused synthesis of a novel family of stable high-entropy MAB-phases for applications in extreme environments.