SHORT- AND LONG-RANGE ORDERING IN BINARY ALLOYS.

Starting from a pair interaction model a generalized theory of ordered binary alloys is derived. Such approach is applicable for arbitrary alloy structures with any given number of long- and short-range parameters and also for all possible numbers of interaction potentials and component concentrations. On the base of pair correlation functions a new definition of short-range ordering parameters is proposed. Some explicit forms of correlation functions above critical temperature T//c are obtained. The computed results are compared with experimental data for the case of beta -brass. With the accuracy to third-order perturbation theory, interactions and ordering in 13 coordination shells are considered.