Dendritic growth is one of the most important phenomena during the solidification of alloys. However, solute redistribution on the front of solid-liquid interface may result in nonuniform distribution of concentration between dendrite branches. This often causes microscopic segregation and undermines the properties of materials. In order to control the solidification microstructure of Al–Li alloy, we firstly need to understand in depth the morphological and concentration evolution during dendrite growth. Here, the KKS (S.G. Kim, W.T. Kim, T. Suzuki) phase-field model coupling CALPHAD data is employed. The dependences of the dendrite morphologies and growth kinetics on undercooling or initial solute concentration are qualitatively analyzed. Dendrite growth rate increases slowly when undercooling ΔT is approximately less than 25 °C, and steeply when ΔT>40 °C corresponding to the transition from diffusional dendrite growth into rapid solidification. Accordingly, the obtained morphologies change from dendrite into seaweed crystal. The increase of supersaturation influences dendrite growth similarly in terms of growth rate and morphology. Moreover, through simulation of columnar dendrites growth, we find that the microscopic segregation becomes more severely with decreasing undercooling, or increasing supersaturation. These results demonstrate the capability of the technology---phase-field simulation coupling to CALPHAD in the modelling of microstructure evolution during solidification of alloys.

树枝状生长是合金凝固过程中最重要的现象之一。但是，固-液界面前部的溶质再分布可能会导致枝晶分支之间浓度的不均匀分布。这通常会导致微观偏析并破坏材料的性能。为了控制Al-Li合金的凝固组织，我们首先需要深入了解枝晶生长过程中的形貌和浓度演变。在此，采用耦合CALPHAD数据的KKS（SG Kim，WT Kim，T. Suzuki）相场模型。定性分析了枝晶形态和生长动力学对过冷或初始溶质浓度的依赖性。当过冷ΔT大约小于25°C时，树枝状晶体的生长速度缓慢增加，当ΔT> 40°C对应于从扩散枝晶生长到快速凝固的过渡时，则陡峭。因此，所获得的形态从枝晶变为海藻晶体。过饱和度的增加在生长速率和形貌方面对树突的生长产生类似的影响。此外，通过模拟柱状树枝状晶体的生长，我们发现微观偏析随着过冷度的降低或过饱和度的增加而变得更加严重。这些结果证明了与CALPHAD耦合的技术---相场模拟在合金凝固过程中微观组织演变建模中的能力。所获得的形态从枝晶转变为海藻晶体。过饱和度的增加在生长速率和形貌方面对树突的生长产生类似的影响。此外，通过模拟柱状树枝状晶体的生长，我们发现微观偏析随着过冷度的降低或过饱和度的增加而变得更加严重。这些结果证明了与CALPHAD耦合的技术---相场模拟在合金凝固过程中微观组织演变建模中的能力。所获得的形态从枝晶转变为海藻晶体。过饱和度的增加在生长速率和形貌方面对树突的生长产生类似的影响。此外，通过模拟柱状树枝状晶体的生长，我们发现微观偏析随着过冷度的降低或过饱和度的增加而变得更加严重。这些结果证明了与CALPHAD耦合的技术---相场模拟在合金凝固过程中微观组织演变建模中的能力。