A quantitative phase-field model combining with front-tracking method for polycrystalline solidification of alloys
A quantitative phase-field model combining with front-tracking method for polycrystalline solidification of alloys
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DOI：
10.1016/j.commatsci.2015.04.003
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发表时间：
2015-06
影响因子：
3.3
通讯作者：
Yun-Neng Chen;X. Qi;Dianzhong Li;X. Kang;N. Xiao
中科院分区：
文献类型：
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作者：
Yun-Neng Chen;X. Qi;Dianzhong Li;X. Kang;N. Xiao
由于单个晶体在固体和扩散界面层中的取向是恒定的，因此可以耦合锐界面模型来计算多晶生长的相场模拟中的取向。在这里，一个二维相场模型与前沿跟踪方法相结合，用于模拟凝固过程中的多晶生长。在该模型中，定量相场的稀二元合金的缓慢凝固的描述扩散固液界面的动态演变，而前端跟踪方法是用来跟踪每个晶粒的空间依赖取向。由于该模型仅用一个序参量描述凝固过程中的相变，因而计算效率高，克服了相场法求解多晶生长的缺点。首先对所建立的模型进行求解，模拟了不同取向的自由等轴枝晶在过冷熔体中的生长过程。比较结果表明，该模型能够准确地计算出目标的方位。其次，将该模型扩展到多等轴枝晶的凝固模拟。对模拟晶体的生长行为进行了表征和分析，结果表明，该模型能够定量、有效地预测合金凝固过程中大量、大尺度晶体的生长动力学。
As the orientation of an individual crystal is constant in solid and diffusive interface layer, a sharp interface model can be coupled to calculate the orientation in phase-field simulation of polycrystalline growth. Here, a two-dimensional phase-field model in combination with the front-tracking method is provided for simulating polycrystalline growth during solidification. In this model, the quantitative phase-field formulations for slow solidification of dilute binary alloys are employed to describe the dynamical evolution of diffusive solid–liquid interface while the front-tracking method is utilized to track the spatial dependent orientation of each grain. Because of the high computing efficiency that is resulted from only one order parameter used to depict the phase transformation during solidification, the model overcomes the disadvantage of reported phase-field approaches for polycrystalline growth. The built model was firstly solved to simulate a free equiaxed dendrite with different orientations growing from undercooled melt for benchmarking. The comparison results indicate that the model is able to compute the orientation exactly. Secondly, the model was extended to simulate the solidification with many equiaxed dendrites. The growth behaviors of the simulated crystals were characterized and analyzed, which demonstrate that the model is feasible to quantitatively and efficiently predict growth dynamics of crystals in a large number and scale during solidification of alloys.