| The development and application of micro computer simulation is the best way to apply the theory to the actual production. Phase-field method can be used to describe the complicated morphologies of dendritic growth without explicitly tracking the complex phase boundaries. It is expected as a powerful tool to describe complex phase transitions in non-equilibrium state. It is the frontier domain of the numerical simulation during solidification processes at present.Based on KKS model which couples the phase field and concentration field, the dendritic growth process model for Ni-Cu alloy during isothermal solidifications was developed. The solute distribution of nickel-copper alloy during the metal solidification was simulated, the effects of supercooling(ΔT) on the highest solute concentration in front of the dendrite tip and solute segregation ratio were studied emphatically. The results indicate that the, the larger the supercooling ΔT is, the higher the concentration maximum value in front of the dendrite tip is, the severer the microsegregation is. The supercooling can trigger the growth of the secondary arms, and increase the growth rate of the primary dendrite. As the supercooling increasing, the microsegregation increases.Based on the WBM II model which couples the phase field and concentration field, a new definition and analysis of the solute concentration in the interfacial region is set up to make it more realistic. The solute distributio n of nickel-copper alloy during the metal solidification was simulated, the effects of interface thickness on the highest solute concentration in front of the dendrite tip and solute segregation ratio were studied emphatically. The results indicate that the, the smaller the interface thickness is, the higher the concentration maximum value in front of the dendrite tip is, the severer the micro segregation is. The small interface thickness can trigger the growth of the secondary arms, and increase the growth rate of the primary dendrite. |
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