Phase-field Simulation Of Non-isothermal Dendritic Growth Of Binary Alloy

Phase field method can simply simulate the complicated morphology of dendritic in the process of solidification,finally obtain the rule of how microcosmic structure formed without follow the complicated solid/liquid interface,consequently forecast and control solidification microcosmic structure and capability,effectually reduce the amount of experiment in optimize material and technics design.As one of the most popular international solidification structure simulate research field,phase field method become more and more important to the develop of metal materials solidicaiton process simulation.Isothermal phase field control method ignored the release of latent heat in the process of solidification,predigested phase field control equation.In this paper,a non-isothermal phase field control equation was built on the base of isothermal phase field control equation that the release of latent heat in the process of solidification is considered,effectively coupling phase field equation,solute field equation and temperature field equation,almost exactly simulated the solidification process, reappearanced the solidification process,using correlation software and effective method to analyze and discuss the simulation result.Meanwhile,in order to settle the problem of complicated compute work which is formed by the quantitative difference of thermal diffusion and solute diffusion,separately dispersed the phase field equation,solute field equation and temperature field equation by different ways,using C programming language,exactly simulated the process of solidification.Some phenomenons have been found by contrast simulation result of Ni-Cu alloy isothermal and non-isothermal solidification process,release of latent heat will result in higher temperature in solid area than liquid area,the highest temperature appears in the center area of some dendritic growth tips crowd,and increased temperature in solid area will make the alloy remelt,release of latent heat will reduce supercooling of liquid,solid field rate is comparatively small at the some solidification time and the gap became bigger according to time up,dendritic are smaller and fist dendritic are evidently short than in the situation of non-isothermal simulation.Because of latent heat release is considered in the process of non-isothermal simulation,the temperature of dendritic tip is become higher,higher temperature helped solute diffuse,so solid/liquid interface solute concentration is lower,solute concentration in solid field is higher and solute diffuse layer is thicker at the situation of non-isothermal simulation.Thermal diffusion rate almost decide the thickness of thermal diffusion layer,the bigger the thermal diffusion rate,the fast of the thermal diffusion speed,and the easier released latent diffusion.The thicker of the thermal diffusion layer,the lower of the solidification area temperature.