Characterization of precipitate evolution in an artificially aged Al-Zn-Mg-Sc-Zr alloy
Resource
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, 527(4-5), 1068-1073
Journal
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
Journal Volume
527
Journal Issue
4-5
Pages
1068-1073
Date Issued
2010
Date
2010
Author(s)
Wu, Ling-Mei
Seyring, Martin
Rettenmayr, Markus
Wang, Wen-Hsiung
Abstract
The precipitates of an age-hardenable Al-Zn-Mg-Sc-Zr alloy aged at 140 °C have been studied by transmission electron microscopy (TEM). The results are interpreted in terms of structural transformations that involve two types of Guinier-Preston (GP) zones (I and II), the metastable η′ hardening precipitate and the stable phase η-phase (MgZn2). At early stages of ageing, the GPI zones act as nucleation sites for the plate-like η′ phase which precipitates on the {1 1 1}Al plane. The transformation from η′ to η occurs gradually at longer ageing times. The η particles mainly consist of η1 and η2 phase, with small amounts of η4 type and minor quantities of η′ type structures. Furthermore, while a fine dispersion of coherent Al3(Sc,Zr) precipitates is known to have a beneficial effect on the strengthening of the alloy, the formation of GPII zones is suppressed in the presence of zirconium that leads to a reduction in the amount of η′ formed during subsequent ageing. © 2009 Elsevier B.V. All rights reserved.
Type
journal article
File(s)![Thumbnail Image]()
Loading...
Name
423.pdf
Size
23.45 KB
Format
Adobe PDF
Checksum
(MD5):f42a002ece4bd9eea2701b4d60c1c12b