Experimental investigation of normal grain growth in terms of area and topological class
Experimental investigation of normal grain growth in terms of area and topological class
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DOI：
10.1016/0036-9748(85)90053-5
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发表时间：
1985-11
期刊：
影响因子：
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通讯作者：
V. Fradkov;A. Kravchenko;L. Shvindlerman
中科院分区：
文献类型：
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作者：
V. Fradkov;A. Kravchenko;L. Shvindlerman
晶粒生长的过程和由此产生的晶粒结构通常用晶粒尺寸、平均晶粒尺寸和平均晶粒尺寸的时间依赖性来描述。在某些文献（1-3）中，考虑了粒度分布和拓扑类分布（即被排除的颗粒数）。尽管在理论描述（3，4，5，6）和计算机模拟（7，8，9，10）领域做出了相当大的努力，迄今为止还没有实现对这种现象的清晰理解。在（4）中，试图从粒度方面解决这个问题，并在聚结理论中假设，小于某个临界尺寸RE的粒子尺寸减小，而大于K 0的粒子尺寸增大。这种方法没有物理基础，因为二维晶粒的面积增长率由dS=（12，13）给出，其中A是迁移率与表面张力的乘积，其对于系统中的所有晶界都是相同的，T ′）是相邻晶粒的数量，即晶粒的拓扑类。从等式(1)显然，当n< 6时，晶粒面积减小，而当n <6时，晶粒面积增大。面积增长率仅取决于n，这似乎很自然地将正常晶粒增长视为空间面积拓扑类中的演化。应该注意的是，例如。(1)仅对二维为真，对三维没有类似的表达式。本文主要研究二维晶粒结构在相空间（L.~，n），特别是当所有系统参数都表现出缩放行为并且平均晶粒面积随时间线性增长时的正常晶粒生长阶段。由于正常晶粒生长的二维实验比三维实验少，而且由于其作者大多忙于其他问题，因此有必要进行进一步的实验。此外，稍早的晶粒生长计算机模拟已经基于类似晶界和等式的假设进行（14）。（一）.我们的实验是以尽可能接近计算机模型的方式进行的（二维生长，相似的能量和迁移率，没有各向异性）。
The process of grain growth and the resulting grain structure are usually described in terms of grain size, mean grain size and time dependence of mean grain size. In some papers (1-3) size distribution and topological class (ie the number of neighbout grains) distribution are considered. Despite considerable efforts made both in the field of theoretical description (3, 4, 5, 6) and computer simulation (7, 8, 9, 10), no clear understanding of the phenomenon has so far been achieved. In (4) an attempt was made to solve the problem in terms of grain size assuming, als in~ qe theory of coalescence, that~ rains smaller than a certain critical size RE, diminish in size and those greater than K0 grow. There is no physical foundation for this approach because the rate of area growth for a two-dimensional grain is given (12, 13) by dS= where A is product of mobility to surface tension which is the same for all the grain boundaries in the system, T') is the number of neighbour grains, ie the topological class of the grain. From eq.(1) it is clear that when n< 6 the grain area diminishes and whenn]) 6 it increases. The rate of area growth depending only on n it appears natural to consider normal grain growth as evolution in the space area-topological class. It should be noted that eg.(1) is true only for two dimensions and no analogous expression is available for three dimensions. In this paper we examine mosUy the evolution of two-dimensional grain structures in phase space (L.~, n) and specifically the stage of normal grain growth when all the system parameters exhibit a scaling behaviour and the mean grain area grows linearly with time. As two-dimensional experiments in normal grain growth are fewer than the three-dimensional ones and because their authors were mostly preoccupied with other issues, it was necessary to perform further experiments. Moreover, somewhat earlier computer simulations of grain growth had been performed (14) based on the assumption of similar grain boundaries and eq.(1). Our experiments were carried out in a way to approach as close as possible the assumpiions of the computer model (two-dimensional growth, similar energy and mobility, absence of anisotropy).