In situ study of nucleation and growth of the irregular alpha-Al/beta-Al5FeSi eutectic by 3-D synchrotron X-ray microtomography

S. Terzi (1) , J.A. Taylor (2, 3) , Y. Cho (1, 4) , L. Salvo (5) , M. Suery (5) , E. Boller (6) , A.K. Dahle (1, 7)

1 ARC CoE Design Light. Met.
2 CAST CRC
3 Coastal and estuarine research group
4 SNU - Seoul National University [Seoul]
5 SIMaP - Science et Ingénierie des Matériaux et Procédés
6 ESRF - European Synchrotron Radiation Facility
7 QUT - Queensland University of Technology [Brisbane]

In order to better understand the formation of beta-Al5FeSi intermetallic plates during solidification of Al-Si casting alloys, an Al-8% Si-4% Cu-0.8% Fe alloy has been studied by in situ microtomography using high-energy X-rays in the synchrotron. After formation of the aluminium dendrites, the beta phase forms as an irregular eutectic together with eutectic alpha-Al. Only four plates were nucleated in the sample, and all nucleated in the very early stage of the eutectic reaction and subsequently developed into complex connected three-dimensional plates. The plates display very rapid lateral growth and slow thickening, which, together with the observation of imprints of dendrites and ridges in the plates, suggest a very weakly coupled eutectic. (C) 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Mots clés: CASTING ALLOYS; ALUMINUM-ALLOY; AL-CU; THEORETICAL; ASPECTS; SOLIDIFICATION; IRON; INTERMETALLICS; BETA-AL5FESI; STRONTIUM; X-ray microtomography; Aluminium alloys; microstructure; Eutectic solidification; WT.PERCENT CU ALLOY

Domaines: Matériaux

S. Terzi, J.A. Taylor, Y. Cho, L. Salvo, M. Suery, et al.. In situ study of nucleation and growth of the irregular alpha-Al/beta-Al5FeSi eutectic by 3-D synchrotron X-ray microtomography. Acta Materialia, 2010, 58 (16), pp.5370-5380. ⟨10.1016/j.actamat.2010.06.012⟩. ⟨hal-00527810⟩