Effect of Stirring Speed and Flow Pattern on the Microstructure of a Rheocast Al-Mg Alloy

Authors

  • P. Melali
  • P. Ashtijoo
  • B. Niroumand

Keywords:

Semi-solid alloys, Non-dendritic microstructure, Baffle, Stirring speed.

Abstract

The effect of stirring speed and the flow pattern inside a processing crucible were examined in this study. This investigation was performed on the microstructure of mechanically stirred Al-8% Mg. Results reveal that by increasing the stirring speed, morphology of primary particles becomes finer and more spherical. By using baffles, the flow pattern inside the crucible changes. This change causes the melt to accelerate along the crucible wall and producing the finer structure, more spherical and nondendritic. the model, named as nucleation and separation from the wall, posses the ability to explain the microstructure evolution in semi solid fabricated slurry. It must be mentioned that the other model named "fragmentation-agglomeration’’ cannot explain the changes in microstructure by using baffles.

References

D.B. Spencer, R. Mehrabian, M.C. Flemings, J Metallurgical Transactions. (1972), 1925-1932.

M.C. Flemings, J Metallurgical Transactions.22 (1991), 957-981.

R.D. Doherty, H.I. Lee, E.A. Feest, J Materials Scie and Eng. 65 (1984), 181-189.

A. Hellawell, Int Conf Proc of 4th Semisolid alloys and composites, Sheffield (1996), 60.

A. Das, Z. Fan, Int Conf Proc of 7th Semi-Solid Alloys and Composites, Tsukuba (2002), 449.

D.H. Kirkwood, M. Suery, P. Kapranos, H. Atkinson, K.P. Young, Semi-solid Processing of Alloys.1st ed, Verlag Berlin Heidelberg: Springer, (2010).

B. Niroumand, K. Xia, Proceedings of the 8th International Conference on Semi-Solid Processing of Alloys and Composites, Cyprus, (2004), 06-2.

B. Niroumand, Ph.D thesis, The university of Melbourne, (1997).

P. Falak, B. Niroumand, A. Najafizadeh, Evaluation of a New Mechanism. Proceedings of the 8th International Conference on Semi-Solid Processing of Alloys and Composites, Cyprus, (2004), 11-1.

B. Niroumand, P. Falak, J Scripta Materia. 53 (2005), 53-57.

B. Niroumand, K. Xia, J Materials Scie and Eng. 283 (2000), 70-75.

H. Mirzadeh, B. Niroumand, J Alloys & Compd. 474 (2009), 257-263.

M. Reisi ,B. Niroumand,J Alloys and Comp. 470 (2009), 413-419.

A. Desouza, R. Pike, The Canadian Journal of Chem Eng. 50 (1972), 15-23.

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How to Cite

Melali, P., P. Ashtijoo, and B. Niroumand. 2015. “Effect of Stirring Speed and Flow Pattern on the Microstructure of a Rheocast Al-Mg Alloy”. Metallurgical and Materials Engineering 21 (1):35-44. https://metall-mater-eng.com/index.php/home/article/view/131.

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Articles - archived