Prediction of new 212 M2AB2 borides as a promising candidate for future engineering: DFT calculations

Abstract

The elemental diversity is critical for identifying ternary MAB phases with exceptional properties by tuning bonding types and strength between constitutive atoms. The interactions between M and A atoms significantly impact the physical and chemical properties of MAB phases. M2AB2 (where M = Hf, Zr; A = Ga, Ge) was studied using first-principles density functional theory (DFT). Lattice constants (a, c) and internal coordinates have been found after optimization. The lattice parameters in terms of structure exhibit conformity with findings from earlier research. The electronic band structure (EBS) density of states (DOS) and density of states (DOS) have been determined. According to the band structures and density of states investigation, these compounds are electrical conductors. The elastic constants were computed using the stress-strain method. The computed elastic constants and phonon dispersion patterns support this newly found compound's mechanical and dynamical stability. The isotropic elastic moduli bulk modulus (B), shear modulus (G), Young's modulus (E), Poisson's ratio (v), and Vickers hardness (Hv) have been explored within the framework of the Voigte-Reusse-Hill approximation. Specific heat capacity, Debye temperature, entropy, Helmholtz free energy, and internal energy changes of M2AB2 (where M = Hf, Zr; A = Ga, Ge) compounds were investigated using thermodynamic characteristics. The minimum thermal conductivity (Kmin) and melting temperature (Tm) of the compounds have also been computed to assess whether they are suitable as thermal barrier coating (TBC) materials or for high-temperature applications. These compounds' optical properties have been studied, demonstrating their usefulness as coating materials for reducing solar heat absorption. The examined physical characteristics of M2AB2 (where M = Hf, Zr; A = Ga, Ge) are contrasted with those of comparable 212 and 211 MAB phases.