Site preference and alloying effect of platinum group metals in gamma-Ni_3Al

摘要

Using supercell method, the alloying effect of platinum group metals (PGMs) on the lattice parameters of gamma'-Ni_3Al and the site preference of these elements are systematically studied based on first-principle full-potential linearized augmented-plane-wave method. Due to the addition of PGMs, the lattice parameters of gamma' is increased in the order: Mo < Rh < Ru < Ir < Pd < Os < Pt. The calculated site preference energies show that there are three site preference behaviors for PGMs additions in gamma'. The calculations of cohesive energies show that Mo and Ru can stabilize the gamma' phase, further in order to better explain the alloying effect of the two elements in the gamma'-Ni_3Al, the impurity-induced charge density characteristics and the partial density of states are calculated for the systems containing Mo or Ru. The results show that the alloying effect of the two elements in the gamma'-Ni_3Al is different.