Computational Investigation of Ternary Borides Fe3Al2B2, Ru3Al2B2, and Os3Al2B2: Structural, Mechanical, and Phonon Properties

An investigation has been conducted into the structural, mechanical, electronic, vibrational and thermal properties of Fe3Al2B2, Ru3Al2B2, and Os3Al2B2 with the utilization of first-principles density functional theory (DFT) calculations. The optimized lattice parameters of Fe3Al2B2 demonstrate a high degree of congruence with experimental data, thereby validating the efficacy of the utilized approach. The negative formation energies indicate the thermodynamic stability of all compounds while Fe3Al2B2 has the highest structural stability. Mechanical analysis reveals that Os3Al2B2 has the highest bulk modulus, while Fe3Al2B2 possesses the highest shear modulus. Anisotropy mechanical calculations have confirmed that Os3Al2B2 exhibits the strongest anisotropic behavior. Electronic band structure analysis showed that all compounds have metallic nature. Phonon dispersion calculations have been used to confirm the dynamical stability of Fe3Al2B2 and Ru3Al2B2, while Os3Al2B2 has been shown to possess negative phonon modes, thus indicating potential instability. These findings indicate that Fe3Al2B2 is the most mechanically and thermally stable compound and thus suitable for high strength applications, while the significant anisotropy of Os3Al2B2 makes it ideal for applications requiring directional mechanical properties.