Study Of Pure Metal Solidification Process Of The Phase Field Method

Phase-field method is the most effective method in simulating solidification microstruction at present. The phase-field model of pure diffuse and coupled convection of pure metal dendritic growth is derived. The influence of interface anisotropy and noise are considered into the phase-field models. The arithmetic of pure diffuse model are investigate by using the Finite Difference Method. The computational program are programmed by using Visual Fortran 6.0. The simulation result is visible by the application of Array visualizer software. The evolution of dendritic growth in pure metal melt is simulated successfully.In the simulation, the parameter influence of interface thickness, grid spacing, undercooling, anisotropy coefficient and the parameter that controls strength of the coupling between the phase and diffusion field on dendritic grows is investigated seriatim. The calculated results indicated that in order to obtain the reasonable results with the experiments, the value range of the interface thickness is relating to undercooling and anisotropy coefficient, if satisfied steady condition, it should be quite small;grid spacing is choosed 0.4W₀ when no considering noise and 0.8W₀ when incorporating noise;with the increase of undercooling, crystal morphology is varied from dendritic morphology to seaweed morphology;anisotropy coefficient value should be between 0.02⁰.05;the value of coupling coefficient is detemined by physical properties parameter.On base of the essential parameter chosen reasonably, the dendritic morphology of incorporated noise model is simulated successfully. The results show that thermal noise can enhance the emergence of side-branching, the tip operating state is not influenced when magnitude value is smaller, otherwise it would be influenced;noise intensity value does not influence tip operate state.The dendritic tip growth velocity and tip radius and operating steady-state arecalculated, the results is in accord with the classical dendritic growth theory, such as Microcosmic Solvability Theory, Ivantsov Theory and Marginal Stability Theory. Take Nickel for example, the calculated results are good agreement with experimential value, it confirms the validity of the simulation.