Investigation on the elastic, thermodynamic and optical properties of TiBe, TiBe ₂ and TiBe ₃

Abstract The energetic and mechanical stability, the electronic properties, the mechanical, thermal and optical properties of TiBe, TiBe 2 and TiBe 3 are analyzed. The applied pressure and the strain taking on the mechanical and thermodynamic as well as the universal anisotropic properties are also analyzed and elucidated from insight of the electronic structures. The results show that the sorting order of formation energy is TiBe < TiBe 2 < TiBe 3 with thermodynamic and mechanic stability. The increase of the orbitals hybridization between Ti and Be atoms substantiates the strength and hardness being enhanced with the Be increased from 50at% to 75at% while the toughness and hardness appear reversely order. The effects of applied pressure and strain imply that the isotropic pressure not only enhances the strength of TiBe, TiBe 2 and TiBe 3 but also increases their toughness. Differently, the TiBe, TiBe 2 and TiBe 3 are not sensitive to applied strain. The thermodynamic properties indicate the lattice vibration of TiBe is inert while that of TiBe 2 and TiBe 3 are active reversely, resulting only a small number of low–frequency phonons in TiBe are thermally excited. The optical and electrical properties indicate that the inter–band transitions of electrons become more active inside TiBe than that in TiBe 2 and TiBe 3 when the energy greats than 0.5 eV, substantiates TiBe possessing a relatively higher absorption coefficient and conductivity. In comparison with the Be–rich beryllides (VBe 12 , ZeBe 13 ), these Be–poor beryllides outperform mechanical toughness and stability while maintaining acceptable thermal conductivity and melting point, making it a promising low–Be alternatives for fusion applications.