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Title: Atomic dynamics in molten AlCu alloys of different compositions and at different temperatures by cold neutron scattering

The atomic motions in molten Al1-xCux (x=0.10, 0.171 and 0.25) around the eutectic composition (x=0.171) were studied by cold neutron inelastic scattering at three different temperatures (973 K, 1173 K and 1373 K). An alloy of eutectic composition containing the 63Cu isotope was also studied. Self-diffusion coefficients for the Cu ions were determined from the width of quasielastic peaks and were found to decrease slightly with increasing Cu concentration. Longitudinal current correlation functions Jl(Q,E) exhibit at all temperatures and at all compositions a shoulder at energies below 10 meV and one main maximum at higher energies. These features can be interpreted in terms of excitations of acoustic and optic nature. The shape of Jl(Q,E) is sensitive to composition, being considerably more structured for larger Cu content. This can be coupled to the existence of a prepeak in the measured zeroth moment of dynamic scattering function indicating an increased chemical ordering with increasing Cu concentration for all temperatures. Indications for an existence of a liquid–liquid phase transition are presented.
 [1] ;  [2] ;  [2] ;  [3] ;  [1]
  1. University of Rouen
  2. Ames Laboratory
  3. Oak Ridge National Laboratory
Publication Date:
OSTI Identifier:
Report Number(s):
IS-J 7939
DOE Contract Number:
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physica B: Condensed Matter; Journal Volume: 412; Journal Issue: March 2013
Research Org:
Ames Laboratory (AMES), Ames, IA (United States)
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States
36 MATERIALS SCIENCE Molten alloys; Neutron scattering; Structure; Diffusion; Chemical ordering