Precipitation kinetics of Si in aluminium alloys

Autor(en)

Fernando Lasagni, Bernhard Mingler, Myriam Dumont, H.P. Degischer

Abstrakt

The precipitation kinetics of Si in an Al¿1.7 wt.%Si alloy after different thermal treatments has been studied by means of transmission electron microscopy (TEM), dilatometry and differential scanning calorimetry (DSC). The results obtained are explained by a model based on simple nucleation and growth/dissolution laws and are compared with measured precipitate size distributions. The evolution of precipitates in water-quenched samples during linear heating depicts the exothermic formation of platelets and globular Si precipitates (200¿300 °C). The endothermal dissolution of Si platelets starts at lower temperatures than that of the globular precipitates. Coarsening and finally dissolution of globular precipitates is observed with increasing temperature. Samples slowly cooled from the solution treatment temperature present mostly globular precipitates, which are nucleated during cooling. Here, an exothermal effect related to the growth of Si precipitates increasing their volume fraction is observed at relatively high temperatures (350¿460 °C) during linear heating. The formed precipitates are stable up to 460 °C, where the modelled critical radius becomes bigger than most of the Si precipitates formed so far.

Organisation(en)

Physik Nanostrukturierter Materialien

Externe Organisation(en)

Technische Universität Wien, Université Paul-Cézanne Aix-Marseille III

Journal

Materials Science and Engineering A: Structural Materials: Properties, Microstructures and Processing

Seiten

383–391

ISSN

0921-5093

DOI

https://doi.org/10.1016/j.msea.2007.07.008

Publikationsdatum

2008

Peer-reviewed

Ja

ÖFOS 2012

103018 Materialphysik

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/bcdc7a95-62f8-4ed7-b25a-9714e7e9ca6e