Phase-field Method Of Dendrite Growth And Microsegregation During Solidification

The phase-field method is effective tool for the simulation of solidification microstructure. It can implement simulation of the complex morphologies of dendrite growth in metal solidification in stead of tracking the complex solid-liquid interface. The forming rules of microstructure can be obtained based on the simulated microstructure. Consequently, the predicting and controlling the solidification microstructure can also achieved.In this paper, the microsegregation and the evolution of dendrite growth during isothermal solidification of Fe-0.5mol%C alloy and Fe-0.5mol%C-0.1mol%Mn alloy are simulated by using phase field method.The primary contents of this paper are as follows:1. The evolution of dendrite growth during isothermal solidification of Fe-0.5mol%C alloy is simulated by using phase field method. The morphology of dendrite with secondary branch is obtained. And the growth and the competition among the dendritic arms are reappeared in the simulation.2. The solute distribution and microsegregation of dendrite growth during isothermal solidification Fe-0.5mol%C alloy are predicted. There are the solute enrichment and dendrite segregation during the solidification. The concentration in the primary arms is lowest, and the concentration of the liquid phase among the arms is highest due to the solute enrichment. The solute concentration of the dendritic tip is lower than that of the liquid phase among the arms.3. The effect of the undercooling, interface thickness, anisotropy coefficients, the noise coefficients on shapes of dendrites and distribution of solute for dendrite growth are studied, which are the parameters in the phase-field model. The the undercooling has a great influence on the morphology of dendrite , with the increasing of undercooling the solidification fraction increases, the dendrite growth is rapid and the secondary branches are more greater. The anisotropy of crystal can influence the trunk of dendrite, and the noise relates the formation of the secondary arms.4. The dendrite solidification progress of the Fe-0.5mol%C-0.1mol%Mn is simulated. The added third component has influenced on the dendrite morphology and distribute of other solute.