Effect of an abrupt change growth velocity on directionally solidified microstructures of Ni–24.19 wt%Nb hypereutectic alloy
Effect of an abrupt change growth velocity on directionally solidified microstructures of Ni–24.19 wt%Nb hypereutectic alloy
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DOI：
10.1016/j.msea.2007.04.086
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发表时间：
2008-02
期刊：
影响因子：
6.4
通讯作者：
Shuangming Li;Yan-Chong Song;B. Ma;L. Tang;H. Fu
中科院分区：
文献类型：
--
作者：
Shuangming Li;Yan-Chong Song;B. Ma;L. Tang;H. Fu
Microstructure evolution of Ni–24.19wt%Nb hypereutectic alloys was investigated to develop a method to increase the productivity of in situ composite in directional solidification. The results show that at the constant growth velocity of 10μm/s, coarse priamry β-Ni3Nb plate dendrites were firstly precipitated from the liquid. However, at the growth velocity changing abruptly from 1μm/s to 10μm/s, only coupled growth eutectics were observed in the solidification microstructure. The coupled eutectic growth stable at 10μm/s is possibly ascribed to the interface growth temperature of coupled eutecitc exceeding that of β-Ni3Nb single phase. Another probable factor to permit the coupled eutectic growth stable at 10μm/s is the difficult nucleation of β-Ni3Nb phase in front of the eutectic growth interface. By changing solidification process, the productivity for the formation of in situ composite of Ni–24.19wt%Nb hypereutectic alloy is improved by a factor of 5.
