Analysis of diffusive cellular patterns in directional solidification of bulk samples
Analysis of diffusive cellular patterns in directional solidification of bulk samples
复制标题
大块样品定向凝固中的扩散细胞模式分析
DOI：
10.1007/s11661-004-0124-6
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发表时间：
2004
期刊：
影响因子：
--
通讯作者：
B. Kauerauf
中科院分区：
文献类型：
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作者：
L. Sturz;G. Zimmermann;S. Rex;M. Mathes;B. Kauerauf
研究了定向凝固过程中固-液界面处胞状结构的形成和演化。采用丁二腈-丙酮稀释型透明合金样品，在航天飞机上进行了扩散条件下的实验。实验参数和材料性质被选择来引起超临界平面到细胞的小幅度细胞转变。细胞间距和细胞邻居的分布是由CCD图像作为时间的函数确定的。在稳态区，界面上有大约50%的缺陷，呈六方排列。将210微米的平均单元间距与不同的模型进行了比较，其中Lu/Hunt模型符合得最好。最小生成树分析被用来检验细胞模式随时间的无序性。将得到的有序参数与蒙特卡罗模拟产生的参考图样的序参数进行了比较。在这些模拟中，蜂窝组织通常由受高斯噪声干扰的平面格子来模拟。我们通过模拟晶格点之间的最小距离的约束扩展了这个模型，得到了实验上发现的明显的最小间距。利用这种新的抑制模型，我们发现了与实验细胞模式更好的定量一致性。
The onset and evolution of cellular patterns at the solid-liquid interface were investigated in directional solidification. A bulk sample of the diluted transparent alloy succinonitrile-acetone was used and the experiments were carried out under diffusive conditions onboard a Space Shuttle mission. The experimental parameters and material properties were selected to cause a supercritical planar-to-cellular transition to small-amplitude cells. Distributions of cell spacings and cell neighbors were determined from CCD images as a function of time. In the steady-state regime, a hexagonal arrangement on the interface with approximately 50 pct defects was found. The average cell spacing of 210µm was compared to different models, of which the Lu/Hunt model concurred best. A minimal-spanning-tree analysis was carried out to examine the disorder of the cellular patterns as a function of time. The resulting order parameters were compared to those of reference patterns generated from Monte-Carlo simulations. In these simulations cellular organization is often modeled by planar lattices disturbed with Gaussian noise. We have extended this model by the constraint of a minimum distance between the lattice points in analogue to the experimentally found distinct minimum spacings. With this new inhibition model, enhanced quantitative agreement with the experimental cellular patterns was found.
影响因子：
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作者：
PRIM, RC
通讯作者：
PRIM, RC