Core–shell nanoscale precipitates in Al–0.06 at.% Sc microalloyed with Tb, Ho, Tm or Lu

The age-hardening response at 300 °C of Al–0.06Sc–0.02RE (at.%, with RE = Tb, Ho, Tm or Lu) is found to be similar to that of binary Al–0.08Sc (at.%), except that a shorter incubation period for hardening is observed, which is associated with nanoscale RE-rich Al 3(RE 1− x Sc x ) precipitates. In ad...

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Bibliographic Details
Published in:Acta materialia 2010, Vol.58 (1), p.134-145
Main Authors: Krug, Matthew E., Werber, Alexandra, Dunand, David C., Seidman, David N.
Format: Article
Language:English
Subjects:
Aluminum alloys
Applied sciences
Atom-probe field-ion microscopy (AP-FIM)
Exact sciences and technology
Metals. Metallurgy
Microhardness
Precipitation
Rare earth
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Summary:The age-hardening response at 300 °C of Al–0.06Sc–0.02RE (at.%, with RE = Tb, Ho, Tm or Lu) is found to be similar to that of binary Al–0.08Sc (at.%), except that a shorter incubation period for hardening is observed, which is associated with nanoscale RE-rich Al 3(RE 1− x Sc x ) precipitates. In addition, Al–0.06Sc–0.02Tb (at.%) has a much lower peak microhardness than that of Al–0.08Sc (at.%) due to the small solubility of Tb in α-Al(Sc). Peak-age hardening occurs after 24 h, and is associated with a high number density of nanoscale Sc-rich Al 3(Sc 1− x RE x ) precipitates. Analysis by three-dimensional local-electrode atom-probe tomography shows that x increases with increasing atomic number, and that the REs partition to the core of the precipitates.
ISSN:1359-6454
1873-2453
DOI:10.1016/j.actamat.2009.08.074