Evolution of nanoscale precipitates in Al microalloyed with Sc and Er

Richard A. Karnesky, David C. Dunand, David N. Seidman*

*Corresponding author for this work

Research output: Contribution to journalArticle

88 Scopus citations

Abstract

The coarsening kinetics of nanoscale, coherent Al3 (Sc1 - x Erx) precipitates in α-Al during aging of a supersaturated Al-0.06 Sc-0.02 Er (at.%) alloy at 300 °C are studied using transmission electron microscopy and local-electrode atom-probe tomography. Erbium and Sc segregate at the precipitate core and shell, respectively. The matrix supersaturations of Er and Sc, as well as the mean precipitate radius and number density evolve in approximate agreement with coarsening models, allowing the determination of the matrix/precipitate interfacial free energy and solute diffusivities. At 300 °C, the α -Al / Al3 (Sc1 - x Erx) interfacial free energy due to Sc is about twice as large as for α -Al / Al3 Sc. The diffusivity of Er in the ternary alloy is about three orders of magnitude smaller than that of Er in binary Al-0.045 at.% Er and about two orders of magnitude smaller than the diffusivity of Sc in binary Al-Sc. The measured Sc diffusivity is consistent with the literature values.

Original languageEnglish (US)
Pages (from-to)4022-4031
Number of pages10
JournalActa Materialia
Volume57
Issue number14
DOIs
StatePublished - Aug 2009

Keywords

  • Aluminum alloys
  • Coarsening
  • Precipitation
  • Rare-earth elements
  • Scandium

ASJC Scopus subject areas

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

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