First-principles calculations of structural, elastic and electronic properties of AB2 type intermetallics in Mg–Zn–Ca–Cu alloy.

Abstract: Electronic structure and elastic properties of MgCu₂, Mg₂Ca and MgZn₂ phases were investigated by means of first-principles calculations from CASTEP program based on density functional theory (DFT). The calculated lattice parameters were in good agreement with the experimental and literature values. The calculated heats of formation and cohesive energies shown that MgCu₂ has the strongest alloying ability and structural stability. The elastic constants of MgCu₂, Mg₂Ca and MgZn₂ phases were calculated, the bulk moduli, shear moduli, Young's moduli and Poisson's ratio were derived. The calculated results shown that MgCu₂, Mg₂Ca and MgZn₂ are all ductile phases. Among the three phases, MgCu₂ has the strongest stiffness and the plasticity of MgZn₂ phase is the best. The density of states (DOS), Mulliken electron occupation number and charge density difference of MgCu₂, Mg₂Ca and MgZn₂ phases were discussed to analyze the mechanism of structural stability and mechanical properties. [Copyright &y& Elsevier]