Calculation of short range order in Ni-Rh, Ni-Pd and Cu-Rh alloys

Transition metal model pseudopotential (TMMP) technique has been applied to study the short range order (SRO) in nickel alloys Ni100-x-Rhx and Ni100-x-Pdx and a copper alloy Cu100-x-Rhx (x = 2, 5, 8, 11 at. %). All these transition metal alloys form fcc solid solutions for the chosen compositions. The static electrical permittivity ?(q) was taken from the Hubbard-Sham model and/or Geldart-Vosko model to account for the exchange energies and correlation correction factors. Ordering energies and the Warren-Cowley SRO parameters have been calculated for all these alloys. Both models gave almost the same values for both the ordering energies and the Warren-Cowley SRO parameters. The TMMP model is found to predict the correct sign of SRO parameters for all these alloys.