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Artikel
On the formation of macrosegregations in unindirectionnally solidified Sn-Pb and Pb-Sn alloys.
| Författare: |
Shahani, H., Amberg, G.A., Fredriksson, H |
| Dokumenttyp: |
Artikel |
| Tillstånd: |
Publicerad |
| Tidskrift: |
Metallurgical Transactions |
| Volym: |
23A
2301-2311 |
| År: |
1992 |
AbstractThe effect of the natural convection on the formation of macrosegregations has been experimentally and theoretically analyzed. The Sn-10 pct. Pb and Pb-15 pct. Sn alloys were unidirectionally solidified. The temperature gradient and the solidification direction were perpendicular to the gravity vector. The concentration and temperature gradients in the samples cause natural convection. Large macrosegregations were observed in the sample. Two different convection modes were found in the two alloys caused by different density gradients in the two-phase region. This difference in convection causes an enrichment of Pb in the lower part of the last solidified regions in the Sn-10 pct. Pb alloy and an enrichment of Sn in the upper part in the Pb-15 pct. Sn alloy. Computer simulation of the convection mode models the convection pattern and the solidification process during which macrosegregation occurs.
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