First-Principles Study of Ag_3Sn, AgZn_3 and Ag5Zn8 Intermetallic Compounds

摘要

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_3Sn, AgZn_3 and Ag5Zn8. Furthermore, the elastic properties, bonding characteristics, and intrinsic connections of different phases are investigated. The results show that Ag_3Sn, AgZn_3 and Ag5Zn8 have stability structural, plasticity characteristics and different degrees of elastic anisotropy;;Ag_3Sn 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 Ag5Zn8 is strongest, AgZn_3 has the weakest strength, the largest shear resistance, and the highest hardness. Ag5Zn8 has the maximum Anisotropy index and Ag_3Sn has the minimum Anisotropy index. Ag_3Sn、AgZn_3 and Ag5Zn8 are all have covalent bonds and ionic bonds, the ionic bonds decrease in the order Ag_3Sn＞Ag5Zn8＞AgZn_3 and covalent bonds decreases in the order Ag5Zn8＞Ag_3Sn＞ AgZn_3.