Study on solidification process and mechanism of Cu-Ni-Si alloy based on in-situ observation

JIA Fei; ZHAO Dan; LI Yujia; LI Xiaoliang; NING Shaochen; QU Yang

doi:10.7512/j.issn.1001-2303.2021.10.20

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Study on solidification process and mechanism of Cu-Ni-Si alloy based on in-situ observation
Vol. 51, Issue 10, Pages: 119-125(2021)
Published：2021
DOI： 10.7512/j.issn.1001-2303.2021.10.20
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DOI：

JIA Fei, ZHAO Dan, LI Yujia, et al. Study on solidification process and mechanism of Cu-Ni-Si alloy based on in-situ observation[J]. Eletric Welding Machine2021, 51(10): 119-125. DOI： 10.7512/j.issn.1001-2303.2021.10.20.

摘要

利用共聚焦激光扫描显微镜(CLSM)原位观察薄带连铸Cu-3.2Ni-0.75Si合金在不同冷却速率下的凝固过程

定量分析了结晶温度和凝固组织二次枝晶间距依赖于冷却速率的函数关系。结果表明:冷却速率的提高可以显著降低合金的结晶温度

减小合金凝固组织的二次枝晶间距

当冷却速率由0.1℃/s提高至100℃/s时

结晶温度由1 096℃降低至890℃

二次枝晶间距由77.5μm减小至23.5μm

结晶温度和二次枝晶间距依赖于冷却速率的函数关系式分别为TL→S=194×(-v/14)+895和λ2=60×v-0.11。薄带连铸的亚快速凝固特点可以显著细化合金凝固组织

抑制Ni、Si元素的显微偏析

其原因在于冷却速率的提高加大了合金熔体结晶时的初始过冷度。

Abstract

The solidification processes of twin-roll strip casting Cu-3.2 Ni-0.75 Si alloy at different cooling rates were observed in situ by confocal laser scanning microscope（CLSM）

and the functional relationship between the crystallization temperature and the secondary dendrite spacing of the solidified structure depending on cooling rate was quantitatively analyzed.The results show that the increase of cooling rate can significantly reduce the crystallization temperature and the secondary dendrite spacing of the solidified structure. When the cooling rate increases from 0.1 ℃/s to 100 ℃/s

the crystallization temperature decreases from 1 096 ℃ to 890 ℃

and the secondary dendrite spacing increases from 77.5 μm to23.5 μm

the function relations of crystallization temperature and secondary dendrite spacing depending on cooling rate are TL→ S=194×（-v/14）+895 and λ2=60×v-0.11

respectively. The subrapid solidification characteristics of twin roll strip casting can significantly refine the solidification structure of the alloy and inhibit the microsegregation of Ni and Si elements. The reason is that the increase of cooling rate enhances the initial undercooling of the alloy melt during crystallization.