title: Direct imaging of Guinier-Preston zones by high-angle annular detector dark-field scanning transmission electron microscopy.
abstract: We report atomic resolution imaging of Cu-planar precipitates in aged Al-Cu alloys, known as Guinier-Preston (GP) zones, by high-angle annular detector dark-field scanning transmission electron microscopy. Single layered GP-I zones as small as 2 nm in length were resolved among densely populated GP-I zones, whereas double layered GP zones were clearly identified. The images of GP-II zones showed not only the commonly accepted structure, in which single Cu layers are separated by three Al layers, but also a variant, in which double Cu layers are separated by a single Al layer.
authors.forename: T J
authors.initials: TJ
authors.lastname: Konno
authors.forename: M
authors.initials: M
authors.lastname: Kawasaki
authors.forename: K
authors.initials: K
authors.lastname: Hiraga