Solidification behavior and microstructural evolution of the Cr‐Nb eutectic alloy
Solidification behavior and microstructural evolution of the Cr‐Nb eutectic alloy
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DOI：
10.1002/crat.201300030
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发表时间：
2013-07
影响因子：
1.5
通讯作者：
K. Li;S. M. Li;Hong Zhong;Y. Xue;H. Fu
中科院分区：
文献类型：
--
作者：
K. Li;S. M. Li;Hong Zhong;Y. Xue;H. Fu
A series of microstructures including fully coupled eutectic, both α‐Cr and β‐Cr2Nb primary dendrites embedded in eutectic and only β‐Cr2Nb primary dendrites plus eutectic were observed in the arc‐melted Cr‐Cr2Nb eutectic alloy. By employing EPMA analysis performed at the eutectic regions, the eutectic composition of the Cr‐Cr2Nb system was indicated to contain less than 18 at.%Nb. Based on the solidification phase selection involving phase competitive nucleation and growth, the α‐Cr phase was predicted to be the primary nucleating phase and the β‐Cr2Nb the primary growing phase. Under large undercooling conditions, the solidification process was controlled by nucleation, which led to the formation of α‐Cr primary particles. With the decrease in undercooling, the solidification process developed into growth controlling, which caused the occurrence of β‐Cr2Nb primary phase since the actual solidification path of the alloy lay within the hypereutectic region. The explanation was confirmed by the experimental composition analysis.
