Simulation Of Microstructure In Solidification Using Phase-field Method

In this paper, after referring to some literatures internal and overseas about theory of phase-field model, we have derived the governing equations in a phase-field model of pure substance based on the entropy function. The interface anisotropy has been thought over in this phase-field model and a term of noise to produce the side-branches has been introduced into the equation of phase field. At the same time a rectification has been made the equation of the thermal field for a binary alloy. Then the numerical simulation of solidification microstructure using phase-field model of the dendrite growth into the undercooled pure metal and binary single-phase alloy melts are carried on. During the simulation we have applied the Finite Difference method with uniform grids.For clear understanding of the affection that each parameter in phase -field model creates on the phase field pattern of dendrite growth, we have studied the affections of undercooling, anisotropy coefficient, noise and other thermal-physical parameters. The results show that the confirmation of parameters in phase-field model has a very important meaning.Now, the calculational data quantity of program is so large and the running time of program is so long that both of these two reasons have badly limited the farther applying of phase-field method in the microstructure simulation of solidification. In this paper we have adopted a gradually changing area to calculate. This area will be enlarged following the change of thermal field. Of course the coming influenced area during the calculation of next time step will be account for. It shows that the result by usingthis method to accelerate the calculating speed is quite good.