摘要
基于耦合流场的相场模型,采用有限差分法对纯镍凝固过程中多晶粒枝晶生长过程进行模拟,研究了不同对流速度对纯镍多晶粒枝晶生长的影响。结果表明:无强制对流时,枝晶主干光滑无侧向分支产生;有强制对流时,上游枝晶生长受到促进,下游枝晶生长受到抑制,受熔体流动和晶粒间相互影响,枝晶形貌不再对称。随着对流速度的增加,上游枝晶生长加快,流动诱发侧向分支,形成发达的分支结构。中心晶粒上游枝晶尖端生长速度先减小后增大至稳态,最后停止生长。
The phase-field model based on the Tong and Beckermann model coupled with the flow field is used to simulate microstructural dendrite growth of multiple grains for pure metal by way of finite difference method. The effect of different convection velocities on pure metal dendritic crystal growth of multiple grains is studied. The result shows that the principal branch is smooth and no side-branches appear in a free flow. Under forced flow conditions, the grains growth gets promoted on the upstream and inhibited on downstream side. Due to the flow and multiple grains effect each other the dentrite present asymmetric morphologies. As the velocity of convection increases, the growth velocity of upstream dendritic crystal speeded up, flow can enhance the emergence of side branching, well developed side branch structure is formed. The growth velocity of central grain upstream dendritic crystal first decreased and then increased to stable, finally tended to stop growing.
出处
《铸造技术》
CAS
北大核心
2010年第11期1425-1428,共4页
Foundry Technology
关键词
相场法
强制对流
多晶粒
凝固
Phase-field
Forced flow
Multiple grains
Solidification
