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T. Weisz, P. Warczok, T. Ebner, A. Falahati, E. Kozeschnik:
"Simulation of Natural Aging in Al-Mg-Si alloys";
in: "Materials Science Forum - Proceedings LMT2015", Vols. 828-829; Trans Tech Publications, 2015, 468 - 473.

Natural aging during storage of Al-Mg-Si alloys at room temperature can significantly
reduce the maximum strengthening potential (T6) during artificial aging and, therefore, is a key
topic in aluminium research and industry. Many different strategies to understand and reduce the
negative effect of natural aging have been investigated during the last decades, including analysis of
different thermal pre-treatments and considering the effect of different microalloying elements.
From these investigations, the vacancy evolution and the formation of clusters containing Mg and
Si were found to be the governing aging mechanisms behind natural aging. In this work, we present
a model to simulate and predict the behavior of these alloys when subjected to room temperature
aging after solutionizing and demonstrate the effects of different thermal routes and chemical
composition variations. In the implemented model, the evolution of excess quenched-in vacancies
and the effect of solute vacancy traps are considered. Special emphasis is placed on co-cluster
formation and its contribution to strengthening. The thermokinetic software MatCalc is used for the
simulations and the results of the simulations are validated by experimental investigation.

natural aging, Al-Mg-Si, cluster, vacancies, strengthening

http://dx.doi.org/10.4028/www.scientific.net/MSF.828-829.468