| 引用本文: | 刘秋晓,王发展,张院,陈海鹏.Cu-Cr二元合金宏观偏析与温度场的数值模拟[J].材料科学与工艺,2016,24(6):73-78.DOI:10.11951/j.issn.1005-0299.20160613. |
| LIU Qiuxiao,WANG Fazhan,ZHANG Yuan,CHEN Haipeng.Numerical simulation of macrosegregation and temperature field of Cu-Cr two binary alloy[J].Materials Science and Technology,2016,24(6):73-78.DOI:10.11951/j.issn.1005-0299.20160613. |
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| 摘要: |
| Cu-Cr材料是两相复合材料，铬粒子通常以嵌入在铜基体中的形式存在，凝固过程中存在着严重的偏析现象，进而对凝固温度场的分布产生影响.为分析Cr相偏析对温度场分布的影响，基于Eulerian-Eulerian方法，建立了三维凝固偏析模型，利用Fluent模拟计算，偏析模型采用浓度梯度$\nabla {S_{{\rm{Cr}}}}$和分布面积梯度$\nabla {S_{{\rm{Cr}}}}$来表示，得到了Cu-6.5%Cr的凝固偏析分布和温度场分布.结果表明：由于Cr的熔点比较高，当t < ta时，Cr先发生侧向凝固，形成糊状区；同时, Cr相的密度比Cu小，内部Cr相会发生上浮，向合金顶部移动；当t>ta时，顶部的Cr会大量聚集，形成顶部偏析，两侧Cr相“困”于糊状区，形成壁面偏析；随着凝固界面横向推移，壁面偏析对壁面温度场的分布产生影响，Cu的传热系数是Cr的3.85倍，随着Cr相偏析度的增加，降低了基体壁面的传热效率，导致温度梯度变大.研究工作将模拟结果与实验结果进行了对比，证明了模型的准确性.
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| 关键词: 凝固偏析 浓度梯度 分布面积梯度 温度场 传热效率 |
| DOI：10.11951/j.issn.1005-0299.20160613 |
| 分类号:TG111.4；TG146 |
| 文献标识码:A |
| 基金项目:十二五国家科技支撑计划项目(2011BAE31B02);陕西省自然科学基金基础研究计划重点项目. |
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| Numerical simulation of macrosegregation and temperature field of Cu-Cr two binary alloy |
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LIU Qiuxiao1,WANG Fazhan2, ZHANG Yuan2, CHEN Haipeng2
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(1.College of Materials and Mineral Resources,Xi′an University of Architecture and Technology,Xi′an 71000, China; 2.College of Mechanical and Electrical Engineering,Xi′an University of Architecture and Technology,Xi′an 71000, China)
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| Abstract: |
| There is a serious segregation phenomenon during solidification process because Cu-Cr material is a two-phase composite material and Cr usually emended in the copper. So the solidification temperature field distribution was effected seriously by segregation phenomenon. In order to analyze the effect of Cr phase segregation on the distribution of temperature field, a 3D segregation solidification model which adopted concentration gradient and distribution area gradient $\nabla {S_{{\rm{Cr}}}}$ was built based on Eulerian-Eulerian and calculated by Fluent. The Cu-6.5%Cr segregation and the temperature field distribution were gained. The result shows that Cr frozen laterally at t < ta because of the Cr higher melting point and formed mushy zone. While the internal Cr taken place to go up and moved to the alloy top because Cr phase density is smaller than Cu; Owing to the Cr was aggregated at the top at t < ta, the top segregation formed. The Cr phase in the both side was trapped in mushy zone, so the both side formed segregation. With transverse passage of solidification interface, the wall surface temperature field distribution was affected by surface segregation. The heat transfer coefficient of Cu is 3.85 times to Cr. With the increase of Cr phase segregation degree, the matrix wall surface heat transfer efficiency was reduced, and the temperature gradient was increased. Compared to the experimental results, the analytical method was proved to be correct.
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| Key words: segregation concentration gradient distribution area gradient temperature field transfer efficiency |
