کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5436382 1509550 2017 15 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Fragmentation-driven grain refinement in directional solidification of AlCu10wt-% alloy at low pulling speeds
موضوعات مرتبط
مهندسی و علوم پایه مهندسی مواد سرامیک و کامپوزیت
پیش نمایش صفحه اول مقاله
Fragmentation-driven grain refinement in directional solidification of AlCu10wt-% alloy at low pulling speeds
چکیده انگلیسی

The formation of the grain structure in Al-10 wt%Cu alloy during directional solidification was investigated experimentally. The alloy composition was chosen because of its special feature that both the initial melt composition and the solidifying primary Al dendrites have almost identical densities. Therefore, gravity-related effects such as buoyancy or sedimentation acting on nucleated or fragmented solid particles in the melt are expected to be minor. In 3D bulk samples at low solidification velocities, unexpected equiaxed grain growth was found instead of columnar growth. This behavior was investigated in accompanying solidification experiments with thin samples using in-situ X-ray diagnostics. It is demonstrated that fragments detach from the dendrite tip region and move slightly ahead of the solid-liquid interface as they grow. As a result, a dendritic microstructure consisting of elongated equiaxed grains is developed. Accordingly, fragmentation was identified as responsible for grain refinement in the given parameter range.

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ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Acta Materialia - Volume 126, March 2017, Pages 236-250
نویسندگان
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