کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1789546 | 1524380 | 2016 | 14 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Macrosegregation in Al-7Si alloy caused by abrupt cross-section change during directional solidification
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
فیزیک و نجوم
فیزیک ماده چگال
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![عکس صفحه اول مقاله: Macrosegregation in Al-7Si alloy caused by abrupt cross-section change during directional solidification Macrosegregation in Al-7Si alloy caused by abrupt cross-section change during directional solidification](/preview/png/1789546.png)
چکیده انگلیسی
Hypoeutectic Al-7 wt .% Si alloys were directionally solidified vertically downward in cylindrical molds that incorporated an abrupt cross-section decrease (9.5 mm to 3.2 mm diameter) which, after 5 cm, reverted back to 9.5 mm diameter in a Bridgman furnace; two constant growth speeds and thermal gradients were investigated. Thermosolutal convection and cross-section-change-induced shrinkage flow effects on macrosegregation were investigated. Dendrite clustering and extensive radial macrosegregation was seen, particularly in the larger cross-sections, before contraction and after expansion, this more evident at the lower growth speed. This alloy shows positive longitudinal macrosegregation near cross-section decrease followed by negative macrosegregation right after it; the extent of macrosegregation, however, decreases with increasing growth speed. Primary dendrite steepling intensified as solidification proceeded into the narrower section and negative longitudinal macrosegregation was seen on the re-entrant shelves at expansion. A two-dimensional model accounting for both shrinkage and thermo-solutal convection was used to simulate solidification and the resulting mushy-zone steepling and macrosegregation. The experimentally observed longitudinal and radial macrosegregation associated with the cross-section changes during directional solidification of an Al-7Si alloy is well captured by the numerical simulations.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Crystal Growth - Volume 449, 1 September 2016, Pages 134-147
Journal: Journal of Crystal Growth - Volume 449, 1 September 2016, Pages 134-147
نویسندگان
M. Ghods, L. Johnson, M. Lauer, R.N. Grugel, S.N. Tewari, D.R. Poirier,