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Talks and Poster Presentations (with Proceedings-Entry):

F. Lasagni, H. Mohammadian, A. Falahati, H.P. Degischer:
"Volume change of Si-containing Al-alloys during ageing";
Talk: 15th IFHTSE and SMT 20, Wien; 09-25-2006 - 09-29-2006; in: "15th IFHTSE and SMT 20", (2006), Paper ID HT6, 6 pages.



English abstract:
The dimensional stability is of importance for engineering components which are exposed to elevated temperatures or to thermal cycling during secondary processing steps and/or application. Volume changes with temperature and time would affect the performance of components by increasing internal stresses. In this work, the precipitation kinetics of Si in different Si containing Al-base alloys and its effect on the volume change is investigated by dilatometry. The formation and dissolution of Si precipitates is studied after different thermal histories by means of Differential Scanning Calorimetry (DSC), complemented by Transmission Electron Microscopy (TEM) and correlated with the thermal expansion and hardness of the materials. Fast quenching of Al-Si alloys causes Si-supersaturation, which precipitates during reheating producing an additional expansion of up to 0.3 vol.%. This effect is also observed in Al-Si-Mg alloys containing Si > 2Mg at.%, while alloys with Mg in excess follow almost the linear thermal expansion of pure Al. In all cases, the dimensional stability of the alloys depends strongly on their previous thermal history, e.g. cooling rates from casting or solution treatment, and pre-ageing. The effect of Si precipitation recorded by DSC thermograms of Al-Si-Mg alloys can be separated from those of Mg-Si precipitation by comparison with dilatometry.


Online library catalogue of the TU Vienna:
http://aleph.ub.tuwien.ac.at/F?base=tuw01&func=find-c&ccl_term=AC06587327


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