School of Materials Science and Engineering, Tsinghua University, Beijing 100084, People's Republic of China.
Key Laboratory for Advanced Materials Processing Technology, Ministry of Education, Tsinghua University, Beijing 100084, People's Republic of China.
Phys Rev E. 2018 May;97(5-1):053302. doi: 10.1103/PhysRevE.97.053302.
The influence of natural convection on lamellar eutectic growth was determined by a comprehensive phase-field lattice-Boltzmann study for Al-Cu and CBr_{4}-C_{2}Cl_{6} eutectic alloys. The mass differences resulting from concentration differences led to the fluid flow and a robust parallel and adaptive mesh refinement algorithm was employed to improve the computational efficiency. By means of carefully designed "numerical experiments", the eutectic growth under natural convection was explored and a simple analytical model was proposed to predict the adjustment of the lamellar spacing. Furthermore, by alternating the solute expansion coefficient, initial lamellar spacing, and undercooling, the microstructure evolution was presented and compared with the classical eutectic growth theory. Results showed that both interfacial solute distribution and average curvature were affected by the natural convection, the effect of which could be further quantified by adding a constant into the growth rule proposed by Jackson and Hunt [Jackson and Hunt, Trans. Metall. Soc. AIME 236, 1129 (1966)].
自然对流对层状共晶生长的影响通过对 Al-Cu 和 CBr_{4}-C_{2}Cl_{6} 共晶合金的综合相场格子玻尔兹曼研究来确定。浓度差异导致的质量差异引起了流体流动，并采用了强大的并行自适应网格细化算法来提高计算效率。通过精心设计的“数值实验”，探索了自然对流下的共晶生长，并提出了一个简单的分析模型来预测层片间距的调整。此外，通过交替改变溶质膨胀系数、初始层片间距和过冷度，呈现了微观结构的演化，并与经典的共晶生长理论进行了比较。结果表明，自然对流会影响界面溶质分布和平均曲率，通过在 Jackson 和 Hunt 提出的生长规则中添加一个常数，可以进一步量化这种影响[Jackson 和 Hunt，Trans. Metall. Soc. AIME 236, 1129 (1966)]。
