The Simulation Of Isothermal Solidification For Al-Cu Binary Alloy Based On KKS Model

With the development of aviation automotive industry, the production of aluminum alloy castings is increasing rapidly, and the quality of the castings including soundness, microstructure, and mechanical properties is more strict. Modeling of microstructure formation using phase-field model will help to evaluate and optimize the castings processing technology so as to improve their quality, we use Al-2-mole-Cu alloy as an example to study the solidfication because good properties of corrode -resistant and wearable.In this paper, the phase-field model basing on KKS model which coupled the concentration field is used to simulate microstructural dendrite growth of multiple grains for Al-2-mole-Cu alloy. The anisotropies of surface energy and kinetics are considered and the thermal noise is introduced into the energy conservation equation;In the process of simulation, the Visual C++ 6.0 was used to calculate the programme and the Tecplot 9.0 was used to achieve the vision of results.In order to save time of calculation and improve the efficiency, an interpolative method is used to achieve the coupling of the macro field and the micro field.In simulation, the growth of dendrites was expanded from single grain to multiple grains, we mainly studied the influence of different anisotropy coefficients, the grads of solute for initial core coupling with anisotropy coefficients, undercooling oupling with anisotropy coefficients on shapes of dendrites and distribution of solute for single grain;The influence of solute segregation on shapes of dendrites and distribution of solute for two grains and the influence of undercooling on shapes of dendrites and distribution of solute for multiple grains. The perferred growth and any other phenomenons of dendrite growth were reappeared in the simulation. At last, In order to verify the established 2-D model and macro coupled with micro method, the results of simulation are compared with the experimental optical microgaphs of Al-2-mole-Cu alloy, and the predicted dendrite shapes show good agreement with the experiments.