Abstract
Microstructure and creep properties at 300°C were studied in the Al-2wt.%Mg-0.2wt.% OscoSc alloy containing Mg in solid solution and Al3Sc as nano-size precipitates. At large applied stresses, the creep strength is characterized by a stress exponent is ∼5, is significantly improved as compared to binary Al-Sc alloys, and is independent of the size of the Al3Sc precipitates. At small applied stress, a threshold stress was measured, increasing from 9 to 63% of the Orowan stress with increasing Al3Sc precipitates radius form 2 to 20 nm. An existing model for climb-controlled bypass mechanisms is in qualitative agreement with the precipitate radius dependence of the threshold stress. The model is however only valid for coherent precipitates, and the Al3Sc precipitates lose coherency for radii larger than ∼12 nm. For semi-coherent precipitates with radii above 12 nm, the threshold stress remains high, probably because of interface dislocations.
Original language | English (US) |
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Pages | 177-184 |
Number of pages | 8 |
State | Published - Jul 21 2003 |
Event | Hot Deformation od Aluminum Alloys III - San Diego, CA, United States Duration: Mar 2 2003 → Mar 6 2003 |
Other
Other | Hot Deformation od Aluminum Alloys III |
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Country | United States |
City | San Diego, CA |
Period | 3/2/03 → 3/6/03 |
ASJC Scopus subject areas
- Condensed Matter Physics
- Mechanics of Materials
- Metals and Alloys