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Transmission electron microscopy and differential scanning calorimetry studies on the precipitation sequence in an Al–Mg–Si alloy: AA6022

Published online by Cambridge University Press:  03 March 2011

Reza S. Yassar ,
David P. Field  and
Hasso Weiland
Reza S. Yassar*
Affiliation:
School of Mechanical and Materials Engineering, Washington State University, Pullman, Washington 99164-2920
David P. Field
Affiliation:
School of Mechanical and Materials Engineering, Washington State University, Pullman, Washington 99164-2920
Hasso Weiland
Affiliation:
Alcoa Technical Center, Alcoa Center, Pennsylvania 15069
*
a) Address all correspondence to this author. e-mail: [email protected]
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Abstract

The precipitate sequence in a 6022 aluminum alloy was investigated by means of differential scanning calorimetry (DSC), transmission electron microscopy, and Vickers hardness measurements. The solution-treated samples were quenched and then immediately subjected to DSC and isothermal aging experiments. It was observed that in the early stages of aging there are some unknown small precipitates that form prior to the formation of β″ precipitates. Studies on isothermally aged and DSC heated samples suggest that some of the β″ needles transform during growth to lath-shaped precipitates. An alternative precipitation sequence for AA6022 is proposed.

Keywords

AgingSecond phasesTransmission electron microscopy (TEM)
Type
Articles
Information
Journal of Materials Research , Volume 20 , Issue 10 , October 2005 , pp. 2705 - 2711
Copyright
Copyright © Materials Research Society 2005

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