Abstract: In this work, first-principles density functional theory was applied to investigate the effect of variation of Cu Content on the γ-Ni Phase of nickel base alloy from the atomic scale. The total energy, formation enthalpy, cohesive energy,the density of the states and elect on density difference were calculated and used to study the stability of different system including before and after doping. The results show that the doping of Cu atoms reduces the absolute values of formation enthalpy and cohesive energy of the γ-Ni system, and with the increase of the doping concentration, the absolute values of the formation enthalpy and cohesive energy decrease correspondingly, indicating that the system stability reduced when introducing Cu, which is worse with the increasement of Cu. The doping of Cu reduces the hardness and deformation resistance of the system, as well as the oriented bond and bonding ability between atoms, resulting in the reduction of system's ductility. The essential reason for these changes is that the incorporation of Cu changed the charge distribution and interaction around Ni atoms in the system. The trend for experimental results are consistent with that for the first-principles calculation results.

Key words: Cu content, first-principles, γ phase, electronic structure