title: Disorder in Al-li-cu and Al-mn-si icosahedral alloys.
abstract: Faceted dendrites of icosahedral AL(6)Li(3)Cu have been studied by high-resolution x-ray scattering. The samples display long-range icosahedral symmetry both in their diffraction patterns and in their macroscopic morphology. Despite the appearance of well-defined facets, the samples have a high degree of atomic disorder. The Bragg peaks have symmetry-dependent shapes and widths that scale linearly with G perpendicular (phason momentum). The peak widths are surprisingly similar to those found in icosahedral Al-Mn-Si alloys in both their absolute magnitude and their dependence on G perpendicular. The origin of these features in models for the icosahedral phase is discussed.
authors.forename: P A
authors.initials: PA
authors.lastname: Heiney
authors.forename: P A
authors.initials: PA
authors.lastname: Bancel
authors.forename: P M
authors.initials: PM
authors.lastname: Horn
authors.forename: J L
authors.initials: JL
authors.lastname: Jordan
authors.forename: S
authors.initials: S
authors.lastname: Laplaca
authors.forename: J
authors.initials: J
authors.lastname: Angilello
authors.forename: F W
authors.initials: FW
authors.lastname: Gayle