The lattice dynamics of Ni-24%Fe alloy based on an empirical many-body potential

We have developed an empirical many-body potential and used it to investiga te the dynamical behaviours of fee Ni-24%Fe alloy. The new many-body potent ial contains both two- and three-body atomic interactions. The two-body pot ential is expressed by the modified form of the generalized Morse potential and the three-body potential is developed based on the new two-body model potential. The parameters defining the many-body potential for Ni and Fe we re computed following a procedure similar to the method defined by Akgun an d Ugur for fee structure at the lattice constant of the alloy. The radial, tangential and three-body force constants of the alloy were calculated by t he concentration averages of the computed force constants of the component metals. Finally, the phonon frequencies of the alloy along the principal sy mmetry directions were computed using the calculated two- and three-body fo rce constants. The theoretical results were found to be in good agreement w ith the corresponding experimental values.