Ab Initio Investigation on Structural, Elastic and Electronic Properties of eta-Phase Cu4.5Ni1Au0.5Sn5 and Cu5Ni1Sn4.5In0.5 Intermetallic Compounds

摘要

The structural, elastic and electronic properties of quaternary intermetallic compounds eta-Cu4.5Ni1Au0.5Sn5 and eta-Cu5Ni1Sn4.5In0.5 are investigated by an ab initio method. The calculated heat of formation determines preferential occupancy sites for Ni, Au and In atoms which lead to thermodynamically stable compounds. Variation of lattice constants reveals that the change of atomic bonding has a directional discrepancy in eta-Cu4.5Ni1Au0.5Sn5; the polycrystalline moduli obtained from single-crystal elastic stiffness show an increase after both Ni/Au and Ni/In additions. Also, the anisotropy of Young's modulus and shear modulus is significantly weakened in eta-Cu4.5Ni1Au0.5Sn5. The density of states and maps of charge density distribution suggest that the atomic bonding in the quaternary intermetallic compounds is strengthened by the addition of Ni and Au but weakened by the addition of In.