用相场法模拟Fe-0.5mol%C合金枝晶生长的相关参数优化

Correlative Parameters Optimization in Using Phase-Field Model to Simulate Dendritic Growth of Fe-0.5mol%C alloy

用相场法模拟了Fe-0.5mol%C合金的等温枝晶生长过程,分析了过冷度、各向异性强度和界面厚度对枝晶生长过程的影响。计算结果表明:过冷度显著影响枝晶的形貌,过冷度过小则在界面处的扰动被表面张力作用而抵消,二次枝晶退化;过冷度过大则二次枝晶过发达而相互融合。较低的各向异性强度取值会消弱枝晶生长的方向性,取值过大则二次枝晶粗化。同时,过大的界面厚度会导致主枝晶和二次枝晶粗化。

Isothermal dendritic growth in Fe-0.5mol %C alloy was simulated by using the phase-field model.The influence of the supercooling △ T, anisotropy strength v and the interface thickness λ on dendritic growth was investigated. The calculated results showed that the supercooling remarkably influences the morphology of the dendrite. The disturbance in the interface was counteracted by surface tension, and the secondary arms degraded under the condition of lightly supercooling. The more severe the supercooling, the faster the growing velocity of the dendrite, and the secondary arms were fused with each other. The relatively low anisotropy strength would weaken the tendency of dendrite to growth directionally, and too great anisotropy strength would make secondary arm coarse. Meanwhile, too great interface thickness would coarsen the secondary arms.