3D In Situ Imaging of Aluminium Alloys During Solidification
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TECHNICAL PAPER
TP 2601
3D In Situ Imaging of Aluminium Alloys During Solidification L. Salvo • P. Lhuissier • M. Scheel • S. Terzi • M. Di Michiel E. Boller • J. A. Taylor • A. K. Dahle • M. Sue´ry
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Received: 14 July 2012 / Accepted: 13 September 2012 / Published online: 10 October 2012 Ó Indian Institute of Metals 2012
Abstract X-ray tomography has become a widely used 3D characterisation technique in materials science either using laboratory tomographs or large X-rays facilities. The advantage of large X-rays facilities is the high photon flux which allows fast tomography to be performed. With fast acquisition CCD cameras, it is possible to obtain a 3D image of the material in less than 30 s with a spatial resolution of the order of 1 or 2 lm. We will show that this allows to study the influence of copper addition on the formation of intermetallics formation in Al–Si–Fe–Cu alloys: we will show that copper seems to have beneficial effects. With CMOS cameras it is possible to reduce acquisition times down to values of about 0.15 s. We will show that this allows to obtain in situ 3D information on the early stage of solidification in aluminium alloys, only accessible up to now using radiography : the solidification front rate was measured on several individual dendrites an Al–20wt%Cu alloy and estimated to be around 10 lm/s. Keywords Solidification Aluminium alloys Intermetallics In situ X-ray tomography
L. Salvo (&) P. Lhuissier S. Terzi M. Sue´ry Lab SIMAP-GPM2, Universite de Grenoble CNRS, Saint Martin d’He`res, France e-mail: [email protected] M. Scheel M. Di Michiel E. Boller ESRF, Grenoble, France S. Terzi A. K. Dahle ARC Design in Light Metals, University of Queensland, Brisbane, QLD, Australia J. A. Taylor CAST CRC, School of Mechanical and Mining Engineering, University of Queensland, Brisbane, QLD, Australia
1 Introduction X-ray micro-tomography has been widely used since 1996 in materials since it allows 3D images of materials to be obtained non-destructively with a spatial resolution of the order of 1 lm. It can be performed using synchrotron sources or laboratory tomographs since 2000. It has been used to study foams, creep and damage of metals, solidification of light alloys, sintering of metals [1, 2]. In situ 3D solidification studies require fast acquisition times, consequently radiography was first used and provided unique results concerning dendritic or equiaxed growth in metals [3, 4]. With fast CCD cameras it is now possible to obtain a 3D image in less than 20 s and thus study a large number of solidification problems at low cooling rates (less than 0.1 °C/s) and high solid fraction [5, 6]. As an example we will show 3D in situ studies of the nucleation and growth of intermetallics in Al–Si–Fe alloys. The formation of these intermetallics has been widely studied using optical microscopy [7–10]. In situ studies were only performed recently using 2D radiography [11], allowing the growth rate of these intermetallics to be estimated. More recently 3D in situ s
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