深过冷快速凝固组织演化的相场法数值模拟

By the phase-field approach, the dendritic growth behaviors in pure metal and binary single-phase alloy were simulated. Various dendritic growth patterns under different conditions were well described and zendritic growth mechanisms were xploited. The simulation results show that the interface thickness parameter is critical and the selected space step must satisfy . The fixed-temperature boundary condition and Zero-Neumann boundary condition is preferable to different computation regions. In the simulation of equiax-dendritic growth in the undercooled pure melt, the induction of noise can raise the occurrence of the lateral branch, but doesn't alter the steady-state behaviors of the dendritic tip. We have found there exist a solid-liquid chemical potential gradient in the diffusion interface, which lead to the solute trapping phenomenon during the solidification simulation of the undercooled Ni-Cu single-phase alloy. In the undercooled melt, the planar interface growth can be achieved but at last trends to destabilize into the cells interface. Based on the quadtree datastructure, adopt of the adaptive-mesh can greatly reduce the computation time.

利用相场方法,模拟深过冷熔体快速凝固组织的连续演化过程,揭示快速凝固过程中枝晶生长形态,枝晶生长速度,尖端半径与过冷度的内存规律.通过凝固过程中动量场和应力场的计算,结合多重网络加速技术,研究流体流动及应力,材料各向异性对深过冷熔体组织演化的影响,晟葡衷诘淖杂芍だ砺?为深过冷熔体枝晶生长理论模型的建立奠定基础.