Anisotropic in elasticity, sound velocity and minimum thermal conductivity of Al–Cu intermetallic compounds

First-principles calculations were utilized to study the anisotropic in terms of elasticity, sound velocity and minimum thermal conductivity of Al–Cu intermetallic compounds (AlCu, c-AlCu₃, o-AlCu₃, o-Al₂Cu, t-Al₂Cu, Al₃Cu₂ and Al₄Cu₉). There was good agreement between our calculated lattice constants and previous experimental and theoretical results. The compounds' anisotropy of elasticity was estimated. They had different anisotropic elastic properties. The anisotropy in sound velocity showed that the faster mixed mode (v₊) is much greater than that of slower mixed mode (v_-) and pure transverse mode (v_t) for AlCu phase, while the sound velocity of pure longitudinal mode (v_l) is the largest in cubic phase (c-AlCu₃ and Al₄Cu₉), orthorhombic phase (o-AlCu₃ and o-Al₂Cu) and tetragonal phase (t-Al₂Cu). The calculated minimum thermal conductivity of the compounds from the Clarke's model indicated that they had obvious anisotropy.