Wang Shuo, Guo Zhipeng, Kang Jinwu, Zou Meishuai, Li Xiaodong, Zhang Ang, Du Wenjia, Zhang Wei, Lee Tung Lik, Xiong Shoumei, Mi Jiawei
School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081, China.
Institute for Aero Engine, Tsinghua University, Beijing 100081, China.
Materials (Basel). 2021 Jan 21;14(3):520. doi: 10.3390/ma14030520.
In this paper, the dynamics of multi-dendrite concurrent growth and coarsening of an Al-15 .% Cu alloy was studied using a highly computationally efficient 3D phase field model and real-time synchrotron X-ray micro-tomography. High fidelity multi-dendrite simulations were achieved and the results were compared directly with the time-evolved tomography datasets to quantify the relative importance of multi-dendritic growth and coarsening. Coarsening mechanisms under different solidification conditions were further elucidated. The dominant coarsening mechanisms change from small arm melting and interdendritic groove advancement to coalescence when the solid volume fraction approaches ~0.70. Both tomography experiments and phase field simulations indicated that multi-dendrite coarsening obeys the classical Lifshitz-Slyozov-Wagner theory Rn-R0n = kc(t-t0), but with a higher constant of = 4.3.
在本文中，利用计算效率极高的三维相场模型和实时同步加速器X射线显微断层扫描技术，研究了Al-15.%Cu合金多枝晶同时生长和粗化的动力学过程。实现了高保真多枝晶模拟，并将结果与时间演化的断层扫描数据集直接进行比较，以量化多枝晶生长和粗化的相对重要性。进一步阐明了不同凝固条件下的粗化机制。当固相体积分数接近~0.70时，主导的粗化机制从小臂熔化和枝晶间沟槽推进转变为聚结。断层扫描实验和相场模拟均表明，多枝晶粗化遵循经典的Lifshitz-Slyozov-Wagner理论Rn-R0n = kc(t-t0)，但常数较高，为 = 4.3。
