Phase stability, elastic, anisotropic and thermodynamic properties of GdT2Al20 (T = Ti, V, Cr) compounds: A first-principles study

First principles calculations were used to explore the structural stability, mechanical properties, ductile or brittle behavior, anisotropic properties and thermodynamic properties of GdT2Al20 intermetallics. The calculated formation enthalpy and phonon frequencies indicate that GdT2Al20 intermetallics exhibit the structural stability. The elastic constants Cijs and elastic moduli (B, G, E) confirm that GdT2Al20 intermetallics possess the better elastic properties than pure Al. The values of Poisson's ratio v and B/G demonstrate that GdT2Al20 intermetallics are all brittle materials. The anisotropic constants, anisotropic figures (three and two dimensional figures) of Young's modulus and anisotropic acoustic velocities indicate that GdT2Al20 intermetallics are anisotropic, but the degree of anisotropy is small. Electronic properties confirm that the better elastic properties of GdT2Al20 intermetallics are attributed to the bond strength of GdAl bond, Gd-T bond and T-Al metallic bonds. The calculated thermodynamic quantities demonstrate that GdT2Al20 intermetallics exhibit the better thermal physical properties than pure Al at high temperature.