Solidification interface morphology pattern in the undercooled Co-24.0 at.% Sn eutectic melt
Solidification interface morphology pattern in the undercooled Co-24.0 at.% Sn eutectic melt
复制标题
凝固%20界面%20形貌%20花纹%20in%20the%20过冷%20Co-24.0%20at.%%20Sn%20共晶%20熔体
DOI：
10.1016/j.actamat.2011.05.028
复制
发表时间：
2011-08-01
期刊：
影响因子：
9.4
通讯作者：
Zhou, Y. H.
中科院分区：
文献类型：
--
作者：
Liu, L.;Li, J. F.;Zhou, Y. H.
Co-24.0原子% Sn共晶合金熔体在低于平衡共晶温度时有不同程度的过冷。根据凝固组织、晶体取向和晶体生长速度的实验结果，建立了过冷度对凝固行为的影响规律。在所研究的整个过冷度范围内（0-203 K），在快速凝固阶段始终发生α-Co和β-Co（3）Sn（2）相的耦合共晶生长。由于界面能的各向异性较弱，共晶凝固界面在合金熔体中以海藻形态而不是众所周知的枝晶形态前进。但存在175 K的临界过冷度，从该临界过冷度开始，共晶凝固界面由分形变为紧密的海藻图案，并伴随着生长速度的突然增加。在深过冷条件下，随着晶体生长速度的提高，界面尖端稳定性的增强是导致生长模式转变的主要原因。(C)2011 Acta Materialia Inc.由爱思唯尔有限公司出版。保留所有权利。
Co-24.0 at.% Sn eutectic alloy melt was undercooled to different degrees below the equilibrium eutectic temperature. The dependence of solidification behavior on undercooling was established based on the experimental results of the solidification microstructure, crystal orientation and crystal growth velocity. In the entire undercooling range studied (0-203 K), coupled eutectic growth of the alpha-Co and beta-Co(3)Sn(2) phases invariably takes place during the rapid solidification stage. The eutectic solidification interface advances in the alloy melt in seaweed morphologies rather than the well-known dendritic mode due to the weak interface energy anisotropy. But a critical undercooling of 175 K exists, from which the eutectic solidification interface changes from a fractal into a compact seaweed pattern, accompanied with an abrupt increase of growth velocity. At high undercoolings the enhancement of the interface tip stability with the rise of crystal growth velocity should be responsible for the growth mode transition. (C) 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.