Atomic Configurations in Binary Alloys

The complete probability distribution of nearest-neighbor configurations has been inferred for a number of cubic binary alloys from their experimentally determined short-range order parameters. The probability variation method, derived previously, was used to perform the calculations. This procedure, which is used to generate $n$-site probabilities from experimentally measured pair probabilities, requires the physical assumption that the configurational energy of the system can be adequately represented by pairwise interactions whose range does not exceed the diameter of the cluster. Results are presented here for $\beta -\mathrm{CuZn}$, ${\mathrm{Cu}}_3$Au, CuAu, ${\mathrm{Au}}_3$Cu, ${\mathrm{Cu}}_{85.5}$ ${\mathrm{Al}}_{14.5}$, ${\mathrm{Cu}}_{52}$ ${\mathrm{Ni}}_{48}$, and ${\mathrm{Au}}_{60}$ ${\mathrm{Pd}}_{40}$, and the implications for ordering (or clustering) behavior are discussed. Finally, tables of coefficients for the bcc and fcc lattice are given to enable one to carry out this type of analysis for any cubic binary system.