Cluster structure of doped atoms and elastic properties in γ-Ni by first-principles calculations

Abstract

The cluster structure with two doped atoms (M: W, Mo, Cr, Ti, Ta, Nb, Ru, Re, Al, Co) in γ-Ni was constructed and investigated by first-principles calculations. The doped systems had the most stable cluster structure along 〈100〉 directions except for the 〈111〉 direction of Ru. The W, Mo, Cr, Ti, Re, Al, Co and Ru tended to form the “-M-M-” linear cluster structure, while the Ta and Nb formed the “-M-Ni-M-” linear cluster structure. The doped systems were ductile and enhanced with the addition of M atoms except for Ru atom, while only Ru atom improved the Young's modulus and shear modulus. Cr and Co atoms increased the anisotropy factor, while Ti, Ta, Nb and Ru atoms decreased the anisotropy factor. From the electronic basis, the charge redistribution and the orbital hybridization between the M atoms and Ni atoms contributed to the stability of cluster structure. The modulus anisotropy caused by the linear cluster structure was due to the change in differential charge density along different directions.