Novel M₂AB (<i>M</i> = V, Zr, Hf; <i>A</i> = S, Se, Te) MAX Phase Borides: Density Functional Theory‐Based Insights in Mechanical and Thermal Properties

The chemical diversity of MAX phases offers significant potential for the development of advanced materials in the nuclear field. Herein, density functional theory is employed to systematically investigate the influence of variations in M ( M = V, Zr, Hf) and A ( A = S, Se, Te) on the mechanical behavior and thermodynamic properties of M 2 AB phases for nuclear applications. The calculated formation energies of all M 2 AB phases are found to be negative, ranging from −1.243 to −0.130 eV, confirming their thermodynamic stability. Elastic constants are computed, and all compounds satisfied the Born–Huang stability criteria, indicating mechanical stability. Among the studied phases, Hf 2 SeB exhibits the highest ductility, with a Pugh's ratio of 2.46 and a Poisson's ratio of 0.32, suggesting excellent machinability. Additionally, thermodynamic properties reveal that Hf 2 SeB has the lowest Debye temperature of 288 K and lattice thermal conductivity of 4.76 Wm −1 K −1 , making it a promising candidate for thermal barrier coatings. These results highlight the potential of Hf 2 SeB as a superior material for nuclear energy applications, combining thermodynamic stability, mechanical robustness, and thermal protection capabilities.