采用计算效率和计算精度较高的Fourier变换谱分析方法求解Cahn-Hilliard相场方 程, 并耦合热力学数据, 对Cu-Pb过偏晶合金在等温情况下液相分离过程中的颗粒生长 和Ostwald 熟化进行了模拟研究. 结果表明, 合金体系中两液相区中的第二 相颗粒生长和Ostwald 熟化过程可以通过调节能量梯度系数和迁移率系数实现. 在过饱和基体中第二相单个颗粒生长的计算结果表明, 颗粒生长的扩散过程主要是系 统自由能作用的结果, 能量梯度系数γ对颗粒与基体之间的浓度梯度起调节作用. 随着γ的减小, 两液相之间的浓度梯度增大, 颗粒轮廓线的斜率增加. 颗粒半径 的生长速率与经典的Zener理论良好吻合. 模拟了Cu-Pb过偏晶合金不混溶区析出第二 相颗粒半径的分布情况, 随着粗化过程的进行, 归一化颗粒半径的尺寸分布峰值由初始 的小于平均尺寸逐渐向平均尺寸靠近, 且最终超过平均尺寸。
Cahn-Hilliard equation coupling with thermodynamic data is solved by Fourier transformation spectrum method due to the high efficiency and accuracy to simulate particle growth and Ostwald ripening for Cu-Pb monotectic alloy at the isothermal condition. The simulation results show that particle growth and Ostwald ripening for specific Cu-Pb monotectic alloy can be realized by the adjustment of gradient coefficient and mobility ratio. The growth of singular nucleated particles in a supersaturated matrix depends on the adjustment of free energy function and the smaller gradient coefficient, the more distinct steepness of concentration profile is. Growth rate of particle radius is in good agreement with the well accepted Zener’s law. Size distribution of reduced particle radius is computed and the peak of radius distribution changes from approaching the average radius to exceeding it.
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| [1] | |
| [2] | |
| [3] | |
| [4] | |
| [5] | |
| [6] | |
| [7] | |
| [8] | |
| [9] |
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