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Title: A hybrid aluminium alloy and its zoo of interacting nano-precipitates

An alloy with aluminium as its base element is heat treated to form a multitude of precipitate phases known from different classes of industrial alloys: Al–Cu(–Mg), Al–Mg–Si–Cu, and Al–Zn–Mg. Nanometer-sized needle-shaped particles define the starting point of the phase nucleation, after which there is a split in the precipitation sequence into six phases of highly diverse compositions and morphologies. There are several unique effects of phases from different alloy systems being present in the same host lattice, of which we concentrate on two: the replacement of Ag by Zn on the Ω interface and the formation of combined plates of the θ′ and C phases. Using atomically resolved scanning transmission electron microscopy and energy-dispersive X-ray spectroscopy, we investigate the formation mechanisms, crystal structures and compositions of the precipitates. - Graphical abstract: Display Omitted - Highlights: • An aluminium alloy composition in-between the 2/6/7xxx systems was investigated. • Six different phases from the three systems coexist in an over-aged state. • All phases with 〈001〉{sub Al} coherencies can nucleate on 6xxx needle precipitates. • Modified theta′ and omega interfaces are observed.
Authors:
 [1] ; ;  [2] ; ;  [1]
  1. Department of Physics, NTNU, Høgskoleringen 5, NO-7491 Trondheim (Norway)
  2. Materials and Chemistry, SINTEF, Høgskoleringen 5, NO-7491 Trondheim (Norway)
Publication Date:
OSTI Identifier:
22476136
Resource Type:
Journal Article
Resource Relation:
Journal Name: Materials Characterization; Journal Volume: 106; Other Information: Copyright (c) 2015 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ALLOY SYSTEMS; ALUMINIUM ALLOYS; COPPER ALLOYS; CRYSTAL STRUCTURE; HEAT TREATMENTS; INTERFACES; MAGNESIUM COMPOUNDS; PHASE TRANSFORMATIONS; PRECIPITATION; SILICON COMPOUNDS; TRANSMISSION ELECTRON MICROSCOPY; X-RAY SPECTROSCOPY