Phase Field Simulation Of Metal Solidification Process Of Microstructure Formation

Phase-field method is the effective method to simulate microstructure evolution during solidification. Based on free energy function, the phase-field model of pure metal, binary single-phase alloy under isothermal and non-isothermal condition are derived respectively.The interface anisotropy is taken into account and a term of noise to produce the side-branches is introduced into the phase-field models. The governing equations of phase-field models are discretized using the Finite Difference method on uniform grids. The phase-field governing equation and the solute governing equation are both numerically solved using Explicit Finite Difference method (Euler method). The thermal governing equation is numerically solved using an Alternating Direct Implicit method (ADI method), which is unconditionally stable, irrespective of the time step employed.The computational program to simulate succinonitrile-5at% water alloy solidification is programmed by using Visual Fortran 6.0 under Windows XP condition. The microstructure simulation result is visible by the application of Array Visualizer software. The influence of anisotropy coefficient γ, noise intensity α and mesh size Ax on dendrite growth behavior is investigated .It is shown that the equiaxed dendrite morphology can not form if anisotropy coefficient y is 0 or very small while the equiaxed dendrite morphology can be deformed if anisotropy coefficient γ is too large. The simulated results are consistent with the experimental results if the anisotropy coefficient γ value is between 0.02~0.05. The...