First-Principles Study of Ag<sub>3</sub>Sn, AgZn<sub>3</sub> and Ag<sub>5</sub>Zn<sub>8</sub> Intermetallic Compounds

The first-principles calculations by CASTEP program based on the density functional theory is applied to calculate the cohesive energy, enthalpy of formation, elastic constant, density of states and Mulliken population of Ag 3 Sn、AgZn 3 and Ag 5 Zn 8 . Furthermore, the elastic properties, bonding characteristics, and intrinsic connections of different phases are investigated. The results show that Ag 3 Sn、AgZn 3 and Ag 5 Zn 8 have stability structural, plasticity characteristics and different degrees of elastic anisotropy; Ag 3 Sn is the most stable structural, has the strongest alloying ability and the best plasticity. AgZn 3 is the most unstable structure, has the worst plasticity; The strength of Ag 5 Zn 8 is strongest, AgZn 3 has the weakest strength, the largest shear resistance, and the highest hardness. Ag 5 Zn 8 has the maximum Anisotropy index and Ag 3 Sn has the minimum Anisotropy index. Ag 3 Sn、AgZn 3 and Ag 5 Zn 8 are all have covalent bonds and ionic bonds, the ionic bonds decrease in the order Ag 3 Sn>Ag 5 Zn 8 >AgZn 3 and covalent bonds decreases in the order Ag 5 Zn 8 >Ag 3 Sn>AgZn 3 .