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

Matthew E. Krug, Alexandra Werber, David C Dunand, David N Seidman*

*Corresponding author for this work

Research output: Contribution to journalArticle

50 Scopus citations

Abstract

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 Al3(RE1-xScx) 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 Al3(Sc1-xREx) 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.

Original languageEnglish (US)
Pages (from-to)134-145
Number of pages12
JournalActa Materialia
Volume58
Issue number1
DOIs
StatePublished - Jan 1 2010

Keywords

  • Aluminum alloys
  • Atom-probe field-ion microscopy (AP-FIM)
  • Microhardness
  • Precipitation
  • Rare earth

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Polymers and Plastics
  • Metals and Alloys

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