Theoretical investigation of new type of ternary magnesium alloys AMgNi_4 (A=Y, La, Ce, Pr and Nd)

摘要

New ternary magnesium alloys AMgNi_4 (A=Y, La, Ce, Pr and Nd) have been studied by First-Principles calculations within the generalized gradient approximation. The optimized structural parameters were in good agreement with the available experimental data. The calculated cohesive energies and formation enthalpies showed that these alloys had strong structural stability. Then the elastic constants C_(ij) of these AMgNi_4 alloys were calculated, and the bulk modulus B, shear modulus G, Youngs modulus E, Poissons ratio ν and anisotropy value A of polycrystalline materials were derived from the elastic constants, the related mechanical properties were further discussed. The electronic structures were also calculated to reveal the underlying mechanism for the structural stability and the elastic property.