| Original Articles |
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Effect of Low Diffusion Coefficient on Eutectic Instability of Al-25wt%Sm Alloy |
| WANG Nan |
| Department of Applied Physics, Northwestern Polytechnical University, Xi'an 710072 |
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| Cite this article: |
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WANG Nan 2008 Chin. Phys. Lett. 25 4168-4170 |
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Abstract Diffusion coefficient decides the solute diffusion length and is a critical parameter in the selection of microstructure scales and in governing microstructure transitions. Al-25wt%Sm alloy is selected to reveal the impact of low diffusion coefficient on the eutectic instability, and the results are compared with those of Al--Cu alloys. Laser remelting experiments are performed and the transition growth velocity from eutectic to α-Al dendrite is examined. Compared with Al--Cu alloys, the eutectic instability takes place at a velocity more than one order of magnitude smaller. The theoretical calculation by the Trivedi--Magnin--Kurz (TMK) model also predicts that the eutectic will become instable at smaller growth velocity for Al--Sm alloy than Al--Cu alloy, which is ascribed to the low diffusion coefficient.
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| Keywords:
81.30.Fb
81.10.Aj
64.70.Dg
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Received: 17 April 2008
Published: 25 October 2008
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| PACS: |
81.30.Fb
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(Solidification)
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81.10.Aj
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(Theory and models of crystal growth; physics and chemistry of crystal growth, crystal morphology, and orientation)
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64.70.dg
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(Crystallization of specific substances)
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