Columnar-to-equiaxed transition in solidification processing of ALSi7 alloys in microgravity-the CETSOL project

Gerhard Zimmermann (1) , Laszlo Sturz (1) , Bernard Billia (2) , Nathalie Mangelinck-Noël (2) , Dong Rong Liu (2) , Henri Nguyen- Thi (2) , Nathalie Bergeon (2) , Charles-André Gandin (3) , David J. Browne (4) , Christoph Beckermann (5) , Damien Tourret (6) , Alain Karma (6)

1 ACCESS EV
2 IM2NP - Institut des Matériaux, de Microélectronique et des Nanosciences de Provence
3 CEMEF - Centre de Mise en Forme des Matériaux
4 UCD - University College Dublin [Dublin]
5 University of Iowa [Iowa City]
6 Northeastern University [Boston]

This paper gives an overview of the experiments on-board the International Space Station (ISS) performed so far by the CETSOL team. Al-7 wt% Si alloys with and without grain refiners were solidified in microgravity. Detailed grain structure analysis showed columnar growth in case of non-refined alloy, but the existence of a columnar to equiaxed transition (CET) in refined alloy. One main result is a sharp CET when increasing the solidification velocity and a progressive CET for lowering the temperature gradient. Applying a front tracking model this behavior was confirmed numerically for sharp CET. Using a CAFE model both segregation and grain structures were numerically modeled and show a fair agreement with the experimental findings.

Mots clés: Aluminium-Silicon Alloy; Grain Structure; Columnar-to-Equiaxed Transition; Solidification; Microgravity

Domaines: Sciences de l'ingénieur [physics]; Matériaux

Gerhard Zimmermann, Laszlo Sturz, Bernard Billia, Nathalie Mangelinck-Noël, Dong Rong Liu, et al.. Columnar-to-equiaxed transition in solidification processing of ALSi7 alloys in microgravity-the CETSOL project. Materials Science Forum, 2014, 790-791, pp.12-21. ⟨10.4028/www.scientific.net/MSF.790-791.12⟩. ⟨hal-01024435⟩