Numerical simulation of solute undercooling influenced columnar to equiaxed transition of Fe-C alloy with cellular automaton
Numerical simulation of solute undercooling influenced columnar to equiaxed transition of Fe-C alloy with cellular automaton
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溶质过冷影响Fe-C合金柱状到等轴转变的元胞自动机数值模拟
DOI：
10.1016/j.commatsci.2019.05.027
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发表时间：
2019-09
影响因子：
3.3
通讯作者：
Zhu Miaoyong
中科院分区：
文献类型：
--
作者：
Wane Weiling;Wane Zhaohui;Yin Shiwei;Sen Luo;Zhu Miaoyong
柱状晶向等轴晶转变（CET）是影响钢的凝固质量和力学性能的关键。采用元胞自动机方法，建立了一个由枝晶生长和异质形核组成的凝固模型，研究了Fe-C合金微观尺度下的CET行为，以及热条件（温度梯度和冷却速度）和初始碳含量对CET位置、CET类型和内部组织定量特征的影响机制。结果表明，预测的Fe-0.82C合金在给定的温度梯度和冷却速度下的CET图与Hunt模型计算的分析结果一致。在模拟中观察到两种CET类型。柱尖型倾向于低温度梯度和高初始碳含量的条件，而枝间型则相反。不同的条件是熔体过冷度和溶质偏析分布的交互作用。降低热梯度、提高冷却速度和初始碳含量可促进CET。同时，内部枝晶组织逐渐由柱状-等轴混合型向等轴型转变。在高温度梯度、弱冷却速度和低初始碳含量范围内，CET位置、枝晶内径的平均值和均方差变化剧烈，随着温度梯度的减小、冷却速度和初始碳含量的增加，CET位置、枝晶内径的平均值和均方差变化平缓。因此，内部枝晶变得更细和更均匀。热条件直接影响过冷度分布，而初始碳含量通过枝晶生长速度和凝固时间起作用。
The columnar to equiaxed transition (CET) is crucial to the solidification quality and the mechanical property of steels. With the cellular automaton approach, the present work developed a solidification model that consists of dendritic growth and heterogeneous nucleation to investigate the CET behaviors of Fe-C alloys at the microscopic scale, as well as the influencing mechanisms of thermal conditions (thermal gradient and cooling rate) and the initial carbon contents on the CET location, CET type and quantitative characteristics of the inner structure. The results show that the predicted CET map that illustrates whether the CET occurs or not at given thermal gradients and cooling rates for the Fe-0.82C alloy in weight percentage agrees with the analytical result calculated with the Hunt model. Two CET types are observed in the simulation. The columnar-tip type prefers conditions with low thermal gradients and high initial carbon contents, while it is the opposite for the interbranch type. The difference in conditions is an interaction effect of the distributions of the melt undercooling and the solute segregation. The CET is promoted by decreasing the thermal gradient and by increasing the cooling rate and the initial carbon content. Meanwhile, the inner dendritic structure gradually changes from the columnar-equiaxed mixed type to the equiaxed type. The CET location and the average and the mean square deviation of the inner dendritic diameter change sharply within the high thermal gradient, weak cooling rate and low initial carbon content range and become gentler with the decrease in the thermal gradient and the increase in the cooling rate and the initial carbon content. Therefore, the inner dendrites become finer and more uniform. Thermal conditions directly influence the undercooling distribution, whereas the initial carbon content works through the dendritic growth velocity and the solidification time.
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DOI：
10.1080/10407790490430606
发表时间：
2004-05
期刊：
Numerical Heat Transfer, Part B: Fundamentals
影响因子：
--
作者：
D. Browne;J. D. Hunt
通讯作者：
D. Browne;J. D. Hunt
影响因子：
9.4
作者：
Nastac, L
通讯作者：
Nastac, L
影响因子：
1.8
作者：
Zibing Hou;F. Jiang;G. Cheng
通讯作者：
Zibing Hou;F. Jiang;G. Cheng
DOI：
10.1088/1742-6596/327/1/012004
发表时间：
2011-12
期刊：
Journal of Physics: Conference Series
影响因子：
--
作者：
A. Viardin;L. Sturz;G. Zimmermann;M. Apel
通讯作者：
A. Viardin;L. Sturz;G. Zimmermann;M. Apel
影响因子：
16.1
作者：
J. A. Spittle
通讯作者：
J. A. Spittle