A new preparation process for nanostructured alloys utilizing co-evapo
ration in a continuous gas flow has been developed. Inert gas is injec
ted into a preparation chamber through a nozzle in order to establish
a convectional flow that carries crystallites of one element above an
evaporation source of a second element so that the atoms of the second
source condense at the crystallite's surfaces in the form of a thin c
oating. In this manner Cu crystallites were coated with Bi, resulting
in Bi-doped grain boundaries after consolidation of the Bi-coated Cu c
rystallites. The maximum overall concentration of Bi without formation
of crystalline Bi was 10 at.%, corresponding to one monolayer of Bi a
toms distributed along the grain boundaries. The average grain size in
the consolidated samples was found to depend on the Bi concentration.
Annealing experiments showed that the onset of grain growth was shift
ed to higher temperature for Bi-doped samples.