First-principles investigations on structural stability, mechanical, and thermodynamic properties of La T ₂ Al ₂₀ ( T = Ti, V, Cr, Nb, and Ta) intermetallic cage compounds

Abstract

First principles calculations were used to explore the structural stability, mechanical properties, and thermodynamic properties of LaT 2 Al 20 (T = Ti, V, Cr, Nb, and Ta) intermetallics. The calculated formation enthalpy and phonon frequencies indicate that LaT 2 Al 20 intermetallics exhibit the structural stability. The elastic moduli (B, G, E, and H v ) indicate that these intermetallics possess the better elastic properties than pure Al. The values of Poisson's ratio v and B/G demonstrate that LaT 2 Al 20 intermetallics are all brittle materials. The anisotropy of elasticity and Young's modulus (three-and two-dimensional figures) indicate that LaT 2 Al 20 compounds are anisotropic. Importantly, the calculated thermal quantities demonstrate that LaT 2 Al 20 intermetallics possess the better thermal physical properties than pure Al at high temperatures.