On ordering in solid solutions of Cu-25 at % Au and Cu-75 at % Au

Abstract

Based on the X-ray diffuse scattering (XRDS) method, a methodology for experimental determination of the parameters of short-range order in disordered polycrystalline solid solutions is developed. The method is based on accounting for static displacements in the corresponding coordination spheres. Static displacements are described by introducing parameter \(\beta = \frac{1} {\nu }\frac{{d\nu }} {{dc}} \), where v is the unit-cell volume, and c is the solid-solution concentration. The short-range order parameters of polycrystalline Cu-25 at % Au and Cu-75 at % Au solid solutions are calculated for a large number of coordination spheres using experimental values of the XRDS intensity and a refined methodology. It is established that the values of the short-range order parameters of a polycrystalline solid solution are close to analogous values for the Cu3Au superstructure, despite the different character of the XRDS intensity. This points to the presence of long-range interatomic interactions in these solid solutions.