Geometrical effect of freckle formation on directionally solidified superalloy CM247 LC components
Geometrical effect of freckle formation on directionally solidified superalloy CM247 LC components
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定向凝固高温合金 CM247 LC 部件上斑点形成的几何效应
DOI：
10.1016/j.jallcom.2015.07.016
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发表时间：
2015-11-05
影响因子：
6.2
通讯作者：
Buehrig-Polaczek, Andreas
中科院分区：
文献类型：
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作者：
Hong, Jianping;Ma, Dexin;Buehrig-Polaczek, Andreas
研究了定向凝固高温合金CM247LC构件中斑点形成的几何效应。横截面缩小的成分有利于雀斑的形成，而横截面增大的成分则保持无雀斑状态，分别显示出促进和抑制雀斑形成的作用。利用热电偶和计算机模拟进行了温度测量，以检测几何效应对局部热场的影响。评估的局部凝固条件不能解释相应的雀斑现象，例如为什么在局部温度梯度显著增加的区域，雀斑变得更加明显。结果表明，组分的几何特征可以强烈地改变热溶解对流的储集条件和流动条件，从而比局部热条件更能有效地影响斑点的形成。(C)2015爱思唯尔B.V.保留所有权利。
The geometrical effect of freckle formation was investigated on directionally solidified superalloy CM247 LC components. The components with a reduction in the transverse section were favourable to freckle formation whereas those with an enlargement in the cross-section remained freckle-free, clearly revealing a promoting and a suppressing effects on the onset the freckle formation, respectively. Temperature measurements using thermal couples and computer simulations were performed to detect the geometrical effect on the local thermal field. The evaluated local solidification conditions cannot explain the corresponding freckling phenomena, such as why freckling becomes more pronounced in areas where the local thermal gradient is significantly increased. It is indicated that the geometrical feature of the components can strongly change the reservoir and flow condition for thermosolutal convection, which can therefore more effectively affect the freckle formation than the local thermal conditions. (C) 2015 Elsevier B.V. All rights reserved.