Cluster interactions and physical properties of Altransition-metal alloys

Ising-like interaction parameters are calculated for alloys of Al with the 3d and 4d transition metals. The interactions are obtained by matching to calculated total energies for supercell compounds on an underlying fcc lattice. The dependence of the parameters on the transition-metal d-band filling displays pronounced oscillations, which are interpreted in terms of the width and shape of the electronic density of states. The interactions are used to provide the first unified ab initio description of a wide variety of phenomena in these alloys. Results for heats of solid solution in transition-metal-rich alloys are in good agreement with experimental values for fcc and hcp phases. Observed chemical trends in solid solubilities, including the values in Al-Mn, are confirmed and explained. Effective pair interactions for describing short-range order are in fairly good agreement with empirical values obtained from short-range-order data and other observations.