Estimation of the Critical Temperatures of Order-Disorder Phase Transitions in Cu-Au Alloys Using Short-Range Order Parameters

摘要

An expression for calculating the critical temperature of order-disorder transition in face-centered cubic alloys is developed with accounting of pairwise interatomic potential in the first eleven shells. The expression obtained was applied to estimate the critical temperatures for Cu_3Au, CuAu, and CuAu_3 alloys in comparison with experimental data from a phase diagram of the Cu-Au system. Magnitudes of the pairwise interatomic potential in the alloys studied were computed using values of the short-range order parameters which were experimentally obtained from X-ray diffuse scattering intensity. In this computation, the Krivoglaz-Clapp-Moss approximation and Cowley equations were applied.