Vol.60, Nos. 2-3 - Indira Gandhi Centre for Atomic Research

Trans. Indian Inst. Met.
Vol.60, Nos. 2-3, April-June 2007, pp. 281-286
TP 2140
In situ Synchrotron X-ray Imaging of the Solidification
Progress in Metallic Alloys
Joseph Gastaldi 1 , Bernard Billia 2 , Henri Nguyen-Thi 2 , Thomas Schenk 3 , Guillaume Reinhart 2 , Nathalie
Mangelinck 2 , Holger Klein 4 , Jürgen Härtwig 5 , Jose Baruchel 5
1
CRMCN, UPR CNRS 7251, Campus Luminy, Case 913, 13288 Marseille Cedex 9, France
2
L2MP, UMR CNRS 6137, Université Paul Cézanne Aix-Marseille III, Faculté des Sciences de Saint-Jérôme,
Case 142, 13397 Marseille Cedex 20, France
3
Laboratoire de Physique des Matériaux, UMR CNRS 7556, Ecole des Mines de Nancy, Parc de Saurupt, 54 042 Nancy Cedex, France
4
Laboratoire de Cristallographie,UPR CNRS 5031, CNRS, BP 166, 38402 Grenoble Cedex 9, France
5
ESRF, BP 220, 38043 Grenoble Cedex, France
E-mail: gastaldi@crmcn.univ-mrs.fr
(Received 30 June 2006 ; in revised form 20 November 2006 )
ABSTRACT
In situ X-ray imaging of the solidification progress can be carried out, nowadays, in front of the synchrotron sources, by combining
X-ray radiography with X-ray topography. Thereby it is possible to obtain information directly, on the one hand on the shape and
the velocity of the growing interface by means of X-ray radiography, and on the other hand, thanks to X-ray topography, on the strains
and the defects generated at the moving interface by the growth process as well as in the grain volume by internal stress centres and
external thermomechanical stresses. In addition, the interaction of strains and defects, contributing to the formation of the solidification
microstructure observed after cooling, can also be followed during this combined imaging. Some of these feasibilities are highlighted
by presenting various examples of the solidification of opaque alloys, displaying facetted or dendritic growth, we have studied with
the apparatus we have developed to perform such experiments at the ID 19 ESRF (European Synchrotron Radiation Facility –
Grenoble - France) beamline.
Trans. Indian Inst. Met.
Vol.60, Nos. 2-3, April-June 2007, pp. 287-291
TP 2141
Growth Structures, Interface Dynamics and Stresses in Metallic
Alloy Solidification: In situ Synchrotron X-ray Characterisation
B. Billia 1 , J. Gastaldi 2 , H. Nguyen-Thi 1 , T. Schenk 3 , G. Reinhart 1 , N. Mangelinck 1 , B. Grushko 4 , H. Klein 5 ,
J. Härtwig 6 and J. Baruchel 6
1
L2MP, UMR CNRS 6137, Université Paul Cézanne Aix-Marseille III, Marseille, France
2
CRMCN, UPR CNRS 7251, Campus Luminy, Marseille, France
3
Laboratoire de Physique des Matériaux, UMR CNRS 7556, Ecole des Mines de Nancy, Nancy, France
4
IFF, Forschungszentrum Juelich GmbH, Juelich, Germany
5
Laboratoire de Cristallographie,UPR CNRS 5031, CNRS, Grenoble, France
6
ESRF, Grenoble, France
E-Mail: bernard.billia@L2MP.fr
(Received 30 June 2006 ; in revised form 20 November 2006 )
ABSTRACT
In solidification processing, the physical properties are primarily controlled by the microstructure built in the solid. Thus, materials
engineering requires detailed understanding of microstructure formation dynamics. Using in situ and real-time synchrotron X-ray
imaging at the European Synchrotron Radiation Facility, the solidification progress in thin metallic alloys is characterized. On Al -
3.5 wt% Ni alloys, disorienting induced by stress accumulation with the development of columnar dendrites is observed. In particular,
X-ray radiography shows bending of secondary dendrite arms which, in the columnar to equiaxed transition, can be furthermore
precipitated by equiaxed crystal sedimentation. Ledge growth and facetted solid-melt interface are found on AlPdMn quasicrystals.
Increasing the solidification rate, the kinetic undercooling becomes sufficient for nucleation and growth of new grains ahead of the
columnar grains.