Direct observation of stray crystal formation in unidirectional solidification of Sn-Bi alloy by X-ray imaging
Direct observation of stray crystal formation in unidirectional solidification of Sn-Bi alloy by X-ray imaging
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DOI：
10.1016/j.jcrysgro.2003.09.052
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发表时间：
2004-02-15
影响因子：
1.8
通讯作者：
Umetani, K
中科院分区：
文献类型：
--
作者：
Yasuda, H;Ohnaka, I;Umetani, K
使用单色同步加速器辐射的时间分辨 X 射线成像能够原位观察 Sn-21 质量% Bi 合金单向凝固过程中的枝晶生长和碎片枝晶臂的脱离。具有凹入通道的模具用于单向凝固。在折返通道中凝固开始时，在界面破裂并形成枝晶后观察到碎片的脱离。此外，在通过凹角的枝晶以相当高的生长速率横向生长后观察到脱离。在这两种情况下，分离都伴随着生长速度的减慢，其中一些导致了杂散晶体。观察表明，碎片臂的分离可能是金属合金中杂散晶体的来源。 (C) 2003 Elsevier B.V. 保留所有权利。
Time-resolved X-ray imaging with monochromatic synchrotron radiation enabled in situ observation of dendritic growth and detachment of the fragmented dendrite arms during unidirectional solidification of Sn-21 mass% Bi alloys. A mold with a re-entrant channel was used for the unidirectional solidification. At the beginning of the solidification in the re-entrant channel, detachment of the fragments was observed after the interface broke down and formed the dendrites. In addition, the detachment was observed after the dendrites passing the re-entrant corner laterally grew at rather high growth rate. In both occasions, the detachments followed deceleration of the growth rate and some of them resulted in the stray crystals. The observation showed that the detachment of the fragmented arms could be a source of the stray crystals in the metallic alloys. (C) 2003 Elsevier B.V. All rights reserved.