相场法模拟Al-4.5%Cu枝晶生长参数的优化

Optimization of correlative Parameters in Numerical Simulation of Denddtic Dendritic Crystal Growth in Al-4.5%Cu alloy Using Phase-field Model

用相场法模拟了Al-4. 5 %Cu合金的等温枝晶生长过程,分析了网格尺寸、各向异性强度和界面厚度对枝晶生长过程的影响。计算结果表明:随着网格尺寸的减小,二次枝晶臂发达、枝晶尖端光滑;较低的各向异性会削弱枝晶生长的方向性,而较大的各向异性则导致误差噪声;界面厚度增加,则在二次枝晶臂上产生侧枝,但较小的界面厚度枝晶的生长服从于尖锐界面条件。本文给出了各参数的优化值。

Isothermal dendritic crystal growth in AI-4.5%Cu alloy is simulated by using the phase-field model。The influence of the mesh size,anisotropy strength and interface thickness on dendritic growth is investigated.The calculated results show that the secondary arms develop well and the tip becomes smooth with decreasing the mesh size.The lower anisotropy strengh makes the secondary arms grow in different direction,and the higher anisotropy strength results in error noise. The greater the interface thickness,the stronger tendency to form side-branches on secondary arms.The thinner interface thickness leads to the dendritic growth subject to the sharp interface condition. Finally,the optimized parameters are deduced.