摘要
采用耦合溶质场与流场的相场模型,模拟了强迫对流作用下Al-3.0mol%Si合金凝固枝晶的生长过程。研究了强迫对流对枝晶生长形貌、溶质分布、溶质扩散层和微观偏析等的影响。结果表明:在强迫对流作用下,合金的枝晶形貌、溶质分布、溶质扩散层和微观偏析产生了显著的变化。在强迫对流作用下,凝固枝晶呈非对称性生长,上游枝晶的生长速度大于下游,二次枝晶更发达,法向枝晶向上游方向倾斜越严重;上游枝晶尖端前沿的浓度梯度变得越大,溶质扩散层厚度减小,而下游则相反,浓度梯度变得越来越小,溶质扩散层厚度逐渐增大。另外,对流的作用也会使枝晶的微观偏析更严重。模拟结果与凝固理论相吻合。
The dendrite growth process of Al-3.0mol%Si alloy in solidification was simulated using the phase-field model coupled solute-field and flow-field, and the effect of forced convection on the dendritic growth, solute profile, concentration boundary layer and microsegregation were investigated. The results indicate that the dendritic growth, solute profile, concentration boundary layer and microsegregation considerably change with the force flow. The dendritic grows asymmetrically under forced flow; the growth velocity of the upstream tip is faster than the downstream tip; the lateral branching is getting more in upstream direction, and the normal primary arm becomes lopsided. The faster the flow velocity, the greater the solute gradients in the solid/liquid interface regions of the upstream tip, the thinner the diffusion layer before the upstream tip. The downstream tip is opposed to the upstream tip. With the force flow, there is more severe microsegregation in the dendritic. The simulation results are consistent with theoretical analysis results based on the solidification theory.
出处
《铸造技术》
CAS
北大核心
2013年第12期1698-1701,共4页
Foundry Technology
关键词
相场法
强迫对流
微观偏析
二元合金
phase-field
forced flow
microsegregation
binary alloy.
