Grain refinement through fragmentation of dendrites in undercooled melts
Grain refinement through fragmentation of dendrites in undercooled melts
复制标题
DOI：
10.1016/s0921-5093(00)01553-7
复制
发表时间：
2001-05-31
期刊：
影响因子：
6.4
通讯作者：
Schwarz, J
中科院分区：
文献类型：
--
作者：
Herlach, DM;Eckler, K;Schwarz, J
在过冷熔体凝固过程中，广泛观察到的从粗大树枝晶到细小等轴晶的微观组织转变，多年来一直令人费解。在这里，我们描述了最近在解决这个难题方面所取得的进展。我们回顾了一个简单模型的基本元素，该模型假设这些转变是由于树枝晶间熔体凝固后的再辉期间重新熔化树枝晶而导致的。更进一步？回顾了专门为检验该模型的预测而设计的镍-铜合金的详细实验结果。模型预测与实验观测结果总体上有较好的定量一致性。尤其是。该模型预测了四个晶粒细化转变的存在。其中三个是通过实验观察到的。它还描述了组织转变过冷度与再辉后的冷却速度和合金成分的关系。与实验结果一致。(C)2001爱思唯尔科学B，V.保留Ail权利。
The widely observed microstructural transitions from coarse dendritic to fine equiaxed grains in solidification of undercooled melts have been puzzling for many years. Here we describe recent process made in solving this puzzle. We review the basic elements of a simple model that assumes that these transitions result from the fragmentation of dendrites by remelting during the period following recalescence when the interdendritic melt solidifies. Furthermore? are review the results of detailed experiments on Ni-Cu allo)rs specifically designed to test the predictions of this model. A good overall quantitative agreement is obtained between the model predictions and the experimental observations. In particular. the model predicts the existence of four grain refinement transitions. three of which are observed experimentally. it also describes the dependence of the microstructural transition undercoolings on the cooling rate that follows recalescence and on the alloy composition? in agreement with the experimental findings. (C) 2001 Elsevier Science B,V. Ail rights reserved.