The lattice dynamical study of a binary type-II alloy

In the present paper, we have developed a new empirical many-body potential (MBP) and first used it, as an application, to investigate the lattice dyn amics of f.c.c, Ni-12% Fe binary type-II alloy. The new MBP contains both t wo- and three-body atomic interactions. The two-body potential has been exp ressed by the modified form of the generalized Morse potential and the thre e-body potential has been described in terms of the new two-body model pote ntial. The parameters defining the MBP for Ni and Fe have been computed fol lowing a procedure given by Akgun and Ugur, for f.c.c. structure at the lat tice constant of the alloy. The radial, tangential and three-body force con stants of the alloy have been calculated by the concentration averages of t he computed force constants of the component metals. Finally, the phonon fr equencies of the alloy along the principal symmetry directions have been co mputed using the calculated two- and three-body force constants. The theore tical results have been found to be in good agreement with the correspondin g experimental values.