Accurate structure factor determination and electron charge distributions of binary cubic solid solutions

Abstract

Abstract By combining the accurate low-angle X-ray structure factors of binary cubic solid solutions determined by high-energy electron diffraction (HEED) with higher-angle values obtained by interpolation between best pure-element form factors, a complete set of accurate X-ray structure factors for these alloys can be produced. This approach is an improvement over previous analyses of this sort, where the pure-element form factors were considered unchanged by alloying (except for lattice parameter changes). This new method has been applied to the alloy systems CuAu, CuAl and FeCr, where sufficient electron diffraction information is available for a full analysis. The results show that the average low-angle form factors are significantly modified by alloying. These electron charge distribution changes can be explained in terms of the known Fermi surface behaviour of these alloys. In addition to these electron charge distribution studies, the effects of short-range order (s.r.o.) were also investigated. Ch...