First-principles calculations to investigate mechanical, electronic, optical, and thermodynamic properties of Zr-based ternary compounds

Abstract

In the present work, a computationally efficient and accurate methodology based on density functional theory is adopted to expound the structural characteristics, elastic, electronic, optical, and thermodynamic properties of zirconium (Zr)-boron (B)-Iridium (Ir) ternary compounds. The current calculated results reveal that Zr–B–Ir ternary compounds except for the Zr4B15Ir12 are dynamically stable phases at 0 K owing to their positive phonon dispersions. Additionally, C–Zr2BIr6 exhibits the best thermodynamic stability due to its lowest formation enthalpy of −0.974 eV/atom in all calculated Zr–B–Ir compounds. C–Zr2BIr6 phase has the maximum bulk and Young's modulus (E) of 151.18 and 382.51 GPa, showing it has a good stiffness due to its higher E. In addition, the elastic anisotropies of the Zr–B–Ir system are complied with the following order: ZrB4Ir3 > T-Zr2BIr6 > Zr4B15Ir12 > C–Zr2BIr6. The non-spherical distribution of electrons for the C–Zr2BIr6 compound plays a blocking role in preventing the deformation, which is beneficial to enhance the comprehensive properties. The B–Ir bond has the shortest length compared to other bond types, resulting in a higher modulus. Lastly, T-Zr2BIr6 has a better storage optical property due to its larger optical conductivity and energy loss function.

Keywords

• Zirconium alloys
• Mechanical properties
• Thermodynamic properties
• Electronic properties
• First-principles calculations