First-Principles Study of the Structural, Mechanical, Electronic, and Thermodynamic Properties of AlCu 2 M (M = Ti, Cr, Zr, Sc, Hf, Mn, Pa, Lu, Pm) Ternary Intermetallic Compounds.

Based on the first principles, the structural stability, mechanical characteristics, electronic structure, and thermodynamic properties of AlCu₂M (M = Ti, Cr, Zr, Sc, Hf, Mn, Pa, Lu, Pm) are investigated. The calculated results indicate that the AlCu₂Pa crystal structure is more stable and that AlCu₂Pa should be easier to form. All of the AlCu₂M compounds have structural stability in the ground state. Elastic constants are used to characterize the mechanical stability and elastic modulus, while the B/G values and Poisson ratio demonstrate the brittleness and ductility of AlCu₂M compounds. It is demonstrated that all computed AlCu₂M compounds are ductile and mechanically stable, with AlCu₂Hf having the highest bulk modulus and AlCu₂Mn having the highest Young's modulus. AlCu₂Mn has the highest intrinsic hardness among AlCu₂M compounds, according to calculations of their intrinsic hardness. The electronic densities of states are discussed in detail; it was discovered that all AlCu₂M compounds form Al-Cu and Al-M covalent bonds. Additionally, we observe that the Debye temperature and minimum thermal conductivity of AlCu₂Mn and AlCu₂Sc are both larger than those of others, indicating stronger chemical bonds and higher thermal conductivities, which is consistent with the elastic modulus results. [ABSTRACT FROM AUTHOR]