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Talks and Poster Presentations (with Proceedings-Entry):

M. Kumar, C. Poletti, H.P. Degischer:
"Precipitation Kinetics in Age Hardening Al-alloys by Dilatometry and Differential Scanning Calorimetry";
Talk: ICAA 12, Yokohama; Japan; 09-05-2010 - 09-09-2010; in: "Proceedings of the 12th International Conference on Aluminium Alloys", (2010), ISBN: 978-4-905829-11-9; 1009 - 1014.



English abstract:
The precipitation and dissolution of precipitates during heat treatments in the age-hardenable
aluminium alloys are very complex due to the influence of various parameters such as exact
chemical composition and thermal history. The temperature dependence of the instantaneous
thermal expansion coefficient was measured after different heat treatments by dilatometry and
correlated with the heat evolution in differential scanning calorimetry. During continuous heating in
the dilatometer, precipitation and dissolution of Zn2Mg phases in an AW7020 alloy show
retardation and acceleration in the expansion with respect to pure Al, respectively. Si precipitation
results in an acceleration of the expansion in AW6016 alloy during heating, while Mg2Si
precipitation and dissolution do not affect the dilatometry curve, which behaves like pure Al.
Superimposed endo- and exothermic peaks from thermograms can be correlated to the dilatometer
curves of the alloys which indicate the phase changes caused by changes in the atomic volume, i.e.
Si and Zn2Mg precipitation. The dilatometry proved to be a complementary technique for
differential scanning calorimetry to distinguish some steps within the precipitation kinetics.

Keywords:
Al-Zn-Mg alloy, Al-Mg-Si alloy, Precipitation, DSC, Dilatometry.

Created from the Publication Database of the Vienna University of Technology.