Transient Ostwald ripening and the disagreement between steady-state coarsening theory and experiment
Transient Ostwald ripening and the disagreement between steady-state coarsening theory and experiment
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DOI：
10.1016/s1359-6454(00)00342-6
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发表时间：
2001-02-23
期刊：
影响因子：
9.4
通讯作者：
Voorhees, PW
中科院分区：
文献类型：
--
作者：
Snyder, VA;Alkemper, J;Voorhees, PW
研究了微重力条件下铅锡液体中固体锡颗粒的粗化过程。这些实验可以使理论和实验之间进行明确的比较。与由Lifshitz、Slyozov和Wagner等人提出的稳态理论相反，缩放后的粒径分布在固体体积分数为0.1和0.2的样品中演化。在实验过程中，平均粒子半径增加了三倍，但仍未达到稳定状态。此外，在固体体积分数为0.1、0.2和0.3的样品中，尺度空间相关函数也具有时间依赖性。在小于或等于0.3的分数处，所有粗化时间的尺寸分布和相关函数与瞬态粗化理论的预测一致。我们表明，微观结构并没有达到所有体积分数的稳定状态，因此不是自相似的；并且在我们的初始实验条件下，达到稳态粗化所需的时间随着体积分数的增加而增加。在这些实验中，我们怀疑在其他实验中也是如此，瞬态时间足够长，以至于稳态理论无法充分描述微观结构的演变。(C) 2001材料学报Elsevier Science Ltd.出版。版权所有。
The coarsening of solid-Sn particles in a Pb-Sn liquid has been studied under microgravity conditions. These experiments permit an unambiguous comparison between theory and experiment to be made. In contrast to steady-state theories, such as those due to Lifshitz and Slyozov and Wagner, the scaled particle size distributions evolve in samples containing 0.1 and 0.2 volume fractions of solid. Steady state was nor reached even though the average particle radius increased by a factor of three during the experiment. In addition, the scaled spatial correlation functions were also found to be time dependent in samples containing 0.1, 0.2, and 0.3 volume fractions of solid. The size distributions and correlation functions for all coarsening times at the fractions less than or equal to0.3 agree with the predictions of a theory for transient coarsening. We show that the microstructures have not reached the steady-stare regime for all volume fractions, are thus not self-similar: and that given our initial experimental conditions the time required to reach steady-state coarsening increases with increasing volume fraction. In these experiments, and we suspect in others as well, the transients are sufficiently long that steady-state theories cannot adequately describe the evolution of the microstructure. (C) 2001 Acta Materialia Inc. Published by Elsevier Science Ltd. All rights reserved.