相场法模拟Al-Cu合金连续冷却枝晶生长

Phase Field Modeling of Dendritic Growth of Al-Cu Alloy during Continuous Solidification Process

采用相场、浓度场耦合的相场法,模拟了A l-Cu合金连续冷却条件下的枝晶生长过程.与以往的研究不同,本文通过指定过冷度序列,用一系列的等温凝固逼近连续冷却过程,因此避免了传统计算中温度场与相场分别采用宏观和微观两套网格及时间步长的问题.相场参数通过有限薄界面条件(thin interface lim it)获得,模拟中考虑了各向异性、浓度扰动等影响.同时通过浓度场计算分析了晶内偏析现象.

The dendritic growth of A1-Cu alloy during continuous solidification is simulated by coupling the phase field to the solute field. In this paper, the approximation of continuous solidification with the isothermal solidification is adopted by appointing a series of super-cooling degree, so the unified lattice and time step are used in the present calculation. The macro-grid and time step in temperature field and micro-grid in phase field for the traditional calculation can be avoided. The parameters in phase field equation can be obtained from thin interface limit condition. The effect of anisotropy and random noise is studied in the simulation. The micro-segregation in a dendrite is also analyzed by the concentration field.