Microdomain Model Analysis for Diffuse X-Ray Scattering from Quenched Cu40 and 60 at% Au Alloys

Abstract

Diffuse X‐ray scattering modulated by local atomic order in quenched Cu60Au40 and Cu40Au60alloys is analyzed on the basis of the correlative microdomain model developed by one of the authors. The average size of the domains, which have an off‐stoichiometrically ordered lattice of Llo‐type, is 1.11 nm in the [001] layering direction and 0.88 nm in the direction normal to it for the Cu‐rich alloy, while it is 1.10 and 1.45 nm, respectively, for the Au‐rich alloy. A noticeable antiphase relation is found bstween the domains having the same [001] layering with interdomain distance of 2.7 nm in the [110] and equivalent directions in the former. Similar interdomain cor‐relation is also found in the latter but with larger interdomain distance of 3.5 nm and this change is in accordance with a possible contraction of the Fermi‐surface diameter with increasing gold content.