Microstructure Stability During Creep of Friction Stir Welded AA2024-T3 Alloy

Journal Article · Mon Oct 15 04:00:00 EDT 2018 · Journal of Materials Engineering and Performance

DOI:https://doi.org/10.1007/S11665-017-3122-8· OSTI ID:22863298

Regev, Michael; Rashkovsky, Tal ^[1]; Cabibbo, Marcello; Spigarelli, Stefano ^[2]

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1. ORT Braude College, Department of Mechanical Engineering (Israel)
2. Università Politecnica delle Marche, DIISM (Italy)

The poor weldability of the AA2024 aluminum alloy limits its use in industrial applications. Because friction stir welding (FSW) is a non-fusion welding process, it seems to be a promising solution for welding this alloy. In the current study, FSW was applied to butt weld AA2024-T3 aluminum alloy plates. Creep tests were conducted at 250 and at 315 °C on both the parent material and the friction stir welded specimens. The microstructures of the welded and non-welded AA2024-T3 specimens before and after the creep tests were studied and compared. A comprehensive transmission electron microscopy study together with a high-resolution scanning electron microscopy study and energy-dispersive x-ray spectroscopy analysis was conducted to investigate the microstructure stability. The parent material seems to contain two kinds of Cu-rich precipitates—coarse precipitates of a few microns each and uniformly dispersed fine nanosized precipitates. Unlike the parent material, the crept specimens were found to contain the two kinds of precipitates mentioned above together with platelet-like precipitates. In addition, extensive decoration of the grain boundaries with precipitates was clearly observed in the crept specimens. Controlled aging experiments for up to 280 h at the relevant temperatures were conducted on both the parent material and the welded specimens in order to isolate the contribution of exposure to high temperatures to the microstructure changes. TEM study showed the development of dislocation networks into a cellular dislocation structure in the case of the parent metal. Changes in the dislocation structure as a function of the creep strain and the FSW process were recorded. A detailed creep data analysis was conducted, taking into account the instability of the microstructure.

• OSTI ID: 22863298
• Journal Information: Journal of Materials Engineering and Performance, Journal Name: Journal of Materials Engineering and Performance Journal Issue: 10 Vol. 27; ISSN 1059-9495; ISSN JMEPEG
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM ALLOYS
COMPARATIVE EVALUATIONS
DATA ANALYSIS
DISLOCATIONS
FRICTION
GRAIN BOUNDARIES
NANOSTRUCTURES
PRECIPITATION
SCANNING ELECTRON MICROSCOPY
TRANSMISSION ELECTRON MICROSCOPY
WELDABILITY
WELDING
X-RAY SPECTROSCOPY