Experimental and numerical modeling of equiaxed solidification in metallic alloys
Experimental and numerical modeling of equiaxed solidification in metallic alloys
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DOI：
10.1016/j.actamat.2008.02.041
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发表时间：
2008-08-01
期刊：
影响因子：
9.4
通讯作者：
Herlach, D. M.
中科院分区：
文献类型：
--
作者：
Gandin, Ch. -A.;Mosbah, S.;Herlach, D. M.
在电磁悬浮期间固化的铝 - 波波样品中的一级树突结构和共晶结构测量了成核底油。记录的冷却曲线用于确定萃取速率和固化时间。冶金表征包括使用配备了能量分散性X射线光谱法和SEM图像分析的扫描电子显微镜（SEM）组成测量值。为平均铜组成，共晶结构的体积分数和树突臂间距绘制的分布图显示了很强的相关性。开发了基于质量和热平衡的等函固化模型，以解释测量。该模型预测了液体和固体中扩散的影响，以及在主要树突结构和共晶结构成核之后立即发生的续热的后果。共晶结构的成核材料不冷却是对固化样品中相位分数进行定量预测的关键参数。 （c）2008 Acta Mitalietia Inc.由Elsevier Ltd.发布的所有权利保留。
Nucleation undercoolings are measured for the primary dendritic structure and for the eutectic structure in aluminum-copper samples solidified during electromagnetic levitation. The recorded cooling curves are used to determine the heat extraction rate and the solidification times. Metallurgical characterizations consist of composition measurements using a scanning electron microscope (SEM) equipped with energy-dispersive X-ray spectrometry and analyses of SEM images. The distribution maps drawn for the average copper composition, the volume fraction of the eutectic structure and the dendrite arm spacing reveal strong correlations. An equiaxed solidification model based on mass and heat balances is developed for the interpretation of the measurements. The model predicts the effect of diffusion in the liquid and in the solid, as well as the consequences of the recalescences occurring immediately after the nucleation of the primary dendritic structure and the eutectic structure. The nucleation undercooling of the eutectic structure is shown to be a key parameter for a quantitative prediction of the fraction of phases in the solidified samples. (C) 2008 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.