A real-time synchrotron X-ray study of primary phase nucleation and formation in hypoeutectic Al–Si alloys

Prasad, Arvind, Macdonald, Stuart D., Yasuda, Hideyuki, Nogita, Kazuhiro and StJohn, David (2015) A real-time synchrotron X-ray study of primary phase nucleation and formation in hypoeutectic Al–Si alloys. Journal of Crystal Growth, 430 122-137. doi:10.1016/j.jcrysgro.2015.06.024

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Author Prasad, Arvind
Macdonald, Stuart D.
Yasuda, Hideyuki
Nogita, Kazuhiro
StJohn, David
Title A real-time synchrotron X-ray study of primary phase nucleation and formation in hypoeutectic Al–Si alloys
Journal name Journal of Crystal Growth   Check publisher's open access policy
ISSN 0022-0248
1873-5002
Publication date 2015-11-15
Year available 2015
Sub-type Article (original research)
DOI 10.1016/j.jcrysgro.2015.06.024
Open Access Status File (Author Post-print)
Volume 430
Start page 122
End page 137
Total pages 16
Place of publication Amsterdam, The Netherlands
Publisher Elsevier
Collection year 2016
Language eng
Abstract This work reports the results of real-time X-ray radiography of grain refined and unrefined Al–Si alloys solidified at the SPring-8 synchrotron. The nucleation events were observed and the grain density and growth rate following nucleation were measured. Nucleation of the grain refined alloy samples occurred from the coolest to the hottest parts of the field of view in a sequence that mimicked a forward moving wave. No additional nucleation events occurred between the first nucleated grains and there was no evidence of grains being generated by fragmentation. Measurements of both grain density and growth rate show the effect of Si content and grain refiner (Al3Ti1B master alloy) additions on grain size. While the total number of grains increases in the alloys with added Al3Ti1B master alloy, the growth rates tend to be slower. Furthermore, the growth rate for all alloy compositions fluctuates between slow and fast velocities during the initial stages of growth and then tends towards a low steady state value. This decreasing trend is explained in terms of thermal and solutal field interactions between adjacent growing grains and subsequent grain impingement. These measurements result in a better understanding of the role of nucleation and solute content in influencing further nucleation and the subsequent change in the solid–liquid growth rate.
Keyword Dendrites
Nucleation
Segregation
Solidification
Grain refinement
Interdependence model
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Mechanical & Mining Engineering Publications
Official 2016 Collection
 
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Citation counts: TR Web of Science Citation Count  Cited 2 times in Thomson Reuters Web of Science Article | Citations
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Created: Fri, 28 Aug 2015, 16:14:20 EST by Dr Arvind Prasad on behalf of School of Mechanical and Mining Engineering