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在传统纯物质相场模型的基础上 ,对其中的体系自由能进行重新构造 ,得到一个紧密联系相图且综合考虑了传热、溶质扩散、界面能各向异性和界面动力学各向异性等适用于二元合金枝晶生长的新相场模型 ,并利用该模型结合一种能显著提高计算效率的“临界面点相场大梯度计算域控制法” ,对Al 7Si合金在初始过冷度分别为 3 5K和 5 0K的过冷熔体中等轴枝晶生长进行了模拟 ,得到许多与试验观察相符合的结果 ;同时在枝晶生长过程中跟踪枝晶主轴尖端 ,获得其尖端半径和尖端速率 ,发现随着凝固时间的增加 ,逐渐收敛 ,直到枝晶达到稳定生长 ,而且通过简化KGT模型计算的枝晶尖端的生长速率与模拟值相近。另外 ,就过冷度对等轴枝晶生长的影响进行了分析
Based on the traditional model of phase field of pure matter, the free energies of the system are reconstructed, and a closely related phase diagram is obtained and considering heat transfer, solute diffusion, interfacial energy anisotropy and interfacial kinetic anisotropy Which is suitable for the new phase field model of binary alloy dendrite growth. By using this model combined with a “large gradient domain control method of critical phase point phase field” that can significantly improve the computational efficiency, The dendrite growth in the subcooled melt at 3 5K and 5 0K respectively was simulated and many results consistent with experimental observations were obtained. Meanwhile, the dendrite spindle tip was tracked during dendrite growth to obtain the tip radius and tip Rate and found to gradually converge as the solidification time increases until the dendrite reaches steady growth and the growth rate of the dendrite tip calculated by simplifying the KGT model is similar to the simulated value. In addition, the effect of undercooling on the growth of equiaxed dendrites was analyzed