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Study of the influence of the artificial ageing temperature on the AA2024 alloy microstructure

Radutoiu, Nicoleta and Alexis, Joël and Lacroix, Loïc and Abrudeanu, Marioara and Petit, Jacques-Alain Study of the influence of the artificial ageing temperature on the AA2024 alloy microstructure. (2013) Key Engineering Materials, 550. 115-125. ISSN 1013-9826

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Official URL: http://dx.doi.org/10.4028/www.scientific.net/KEM.550.115

Abstract

For the last 30 years, AA2024 aluminum alloy was very used as structural material in the aerospace industry due to its low density and good mechanical strength. The phenomenon of precipitation hardening in aluminum alloys takes place at relatively low temperature and induces the precipitation of intermetallic particles composed of the main alloying elements i.e., copper and magnesium. The fundamental stage of the age-hardening process consists in the acceleration of the decomposition phenomenon of the supersaturated solid solution, resulting in the coarse intermetallic particle precipitation; stage where the mechanical properties reaches the maximum values, but at the cost of a low corrosion resistance. In this paper, the AA2024 alloy microstructure was studied during the over-ageing process. The over-ageing treatment (T7) is supposed to stabilize the microstructure and the mechanical properties to improve the corrosion resistance. The over-ageing treatment consists in a solution treatment at 495±5°C for 1 hour, quenched into cold water and artificial aged. Three different artificial ageing temperatures were studied: 150°C, 175°C and 190°C. The mechanical properties modifications were followed by Vickers macrohardness measurements. The treatment duration for each temperature (36 days for 150°C, 50 hrs for 175°C and 24 hrs for 190°C) was determined by a given macrohardness reduction. To characterize the over-aged AA2024 alloy microstructure, a statistical analysis of the surface fraction and surface density of intermetallic particles was made. The intermetallic particle dimension distribution, depending on the over-ageing temperature, was also observed. To do so, scanning electron microscope observations were carried out and image analyses were performed from backscattered electron images.

Item Type:Article
Additional Information:Thanks to Trans Tech Publications Inc. editor. The definitive version is available at www.scientific.net/KEM.550.115
HAL Id:hal-00835701
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution:Université de Toulouse > Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE)
Other partners > Universitatea din Pitesti - UPIT (ROMANIA)
Laboratory name:
Funders:
Supporting young PhD Student with frequency by providing doctoral fellowships" – ID 52826 co-financed from the European Social Fund, through the Sectorial Operational Program Development of Human Resources.
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Deposited On:18 Jun 2013 08:02

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