Core–shell nanoscale precipitates in Al–0.06 at.% Sc microalloyed with Tb, Ho, Tm or Lu
✍ Scribed by Matthew E. Krug; Alexandra Werber; David C. Dunand; David N. Seidman
- Publisher
- Elsevier Science
- Year
- 2010
- Tongue
- English
- Weight
- 1018 KB
- Volume
- 58
- Category
- Article
- ISSN
- 1359-6454
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✦ Synopsis
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 1Àx 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 a-Al(Sc). Peak-age hardening occurs after 24 h, and is associated with a high number density of nanoscale Sc-rich Al 3 (Sc 1Àx 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.