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 language | English (US) |
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Pages (from-to) | 134-145 |
Number of pages | 12 |
Journal | Acta Materialia |
Volume | 58 |
Issue number | 1 |
DOIs | |
State | Published - Jan 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