First-principles investigations on structural stability, mechanical, and thermodynamic properties of LaT2Al20 (T = Ti, V, Cr, Nb, and Ta) intermetallic cage compounds** Project supported by the Program for Ph. D Start-up Fund of Liaoning Province of China (Grant No. 201601161).

Abstract

First principles calculations were used to explore the structural stability, mechanical properties, and thermodynamic properties of LaT2Al20 (T = Ti, V, Cr, Nb, and Ta) intermetallics. The calculated formation enthalpy and phonon frequencies indicate that LaT2Al20 intermetallics exhibit the structural stability. The elastic moduli (B, G, E, and Hv) indicate that these intermetallics possess the better elastic properties than pure Al. The values of Poisson’s ratio v and B/G demonstrate that LaT2Al20 intermetallics are all brittle materials. The anisotropy of elasticity and Young’s modulus (three- and two-dimensional figures) indicate that LaT2Al20 compounds are anisotropic. Importantly, the calculated thermal quantities demonstrate that LaT2Al20 intermetallics possess the better thermal physical properties than pure Al at high temperatures.