In situ and real-time 3-D microtomography investigation of dendritic solidification in an Al-10 wt.% Cu alloy
In situ and real-time 3-D microtomography investigation of dendritic solidification in an Al-10 wt.% Cu alloy
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DOI：
10.1016/j.actamat.2009.01.035
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发表时间：
2009-04-01
期刊：
影响因子：
9.4
通讯作者：
Madi, K.
中科院分区：
文献类型：
--
作者：
Limodin, N.;Salvo, L.;Madi, K.
用分辨率为2.8 μ m的同步辐射X射线显微层析术研究了Al-01wt%Cu合金在恒速凝固过程中的显微组织演变。该合金的凝固导致粗枝晶微观结构，其特征在于在随温度变化的固体分数，固-液界面的比表面积和固相的局部曲率。通过分析单个枝晶随固相分数的变化，除了凝固生长外，还可以清楚地识别出至少两种粗化机制。第一种机制涉及重熔小的二次枝晶臂，以利于更大的相邻臂。第二种是聚结次生臂，臂间间距逐渐填充，末端聚结。虽然这种机制优先发生在高固体分数，这些结果表明，在凝固过程中的枝晶显微组织的演变是复杂的，涉及到并发操作的各种机制的发生。因此，原位X射线断层扫描允许重新访问已提出的各种模型来解释凝固过程中的枝晶粗化。(C)2009 Acta Materialia Inc.由爱思唯尔有限公司出版。保留所有权利。
The microstructural evolution of an Al-01 wt% Cu alloy was investigated during solidification at constant cooling rate by in situ synchrotron X-ray microtomography with a resolution of 2.8 mu m. Solidification of this alloy leads to a coarse dendritic microstructure which was fully characterized in terms of variation with temperature of the solid fraction, the specific surface area of the solid-liquid interface and the local curvatures of the solid phase. By analysing the evolution with solid fraction of individual dedrites, at least two coarsening mechanism were clearly identified in addition to solidification growth. The first mechanism involves remelting of small secondary dendrites arms to the benefit of bigger adjacent arms. The second is the coalscence secondary arms, with progressive filling of the inter-arm spacing and coalescence at the tips. Although this mechanism preferentially occurs at high solid fractions, these results show that the evolution of the dendritic microstructure during solidification is complex and involves the occurence of various mechanisms operating concurrently. In situ X-ray tomography thus allows revisiting the various models which have been proposed to account for dendrite coarsening during solidification. (C) 2009 Acta Materialia Inc. Published by Elsevier Ltd. All rigths reserved.