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The relevance of forced melt flow to grain refinement in pure aluminum under a low-frequency alternating current pulse

Published online by Cambridge University Press:  01 February 2016

Limin Zhang*
Affiliation:
Key Laboratory of Space Applied Physics and Chemistry, Ministry of Education, School of Science, Northwestern Polytechnical University, Xi'an, Shanxi 710072, People's Republic of China
Hainan Liu
Affiliation:
Key Laboratory of Space Applied Physics and Chemistry, Ministry of Education, School of Science, Northwestern Polytechnical University, Xi'an, Shanxi 710072, People's Republic of China
Ning Li*
Affiliation:
Key Laboratory of Space Applied Physics and Chemistry, Ministry of Education, School of Science, Northwestern Polytechnical University, Xi'an, Shanxi 710072, People's Republic of China
Juan Wang
Affiliation:
Key Laboratory of Space Applied Physics and Chemistry, Ministry of Education, School of Science, Northwestern Polytechnical University, Xi'an, Shanxi 710072, People's Republic of China
Rong Zhang*
Affiliation:
Key Laboratory of Space Applied Physics and Chemistry, Ministry of Education, School of Science, Northwestern Polytechnical University, Xi'an, Shanxi 710072, People's Republic of China
Hui Xing
Affiliation:
Key Laboratory of Space Applied Physics and Chemistry, Ministry of Education, School of Science, Northwestern Polytechnical University, Xi'an, Shanxi 710072, People's Republic of China
Kaikai Song
Affiliation:
Key Laboratory of Space Applied Physics and Chemistry, Ministry of Education, School of Science, Northwestern Polytechnical University, Xi'an, Shanxi 710072, People's Republic of China
*
a)Address all correspondence to these authors. e-mail: liminzhang_lmss@mail.nwpu.edu.cn
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Abstract

The refinement mechanism of alternating current pulse (ACP) on the solidification macrostructures of pure Al and the characterization of refining efficiency were investigated by embedding the wire mesh in the mold. The experiment results showed that ACP treatment during solidification led to the formation of fine equiaxed grain. There were remarkably differences with respect to the area of fine equiaxed zone inside and outside the tube. Lorentz force, induced melt flow and the rest of intrinsic effects of ACP inside and outside the tube were discussed in the present study. It demonstrated that the forced melt flow could lead to the columnar fragmentation and make the crystal nucleus on the mold wall fall off and drift in the liquid, leading to grain refinement. In addition, Reynolds number was suitable to characterize the refining efficiency of pure Al under ACP.

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Articles
Copyright
Copyright © Materials Research Society 2016 

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Footnotes

Contributing Editor: Jürgen Eckert

References

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