雾化Al-Si合金液滴冷却凝固过程模拟

Modeling of Cooling and Solidification Process of the Atomized Al-Si Alloy Droplets

在群体动力学模型基础上,提出了描述雾化共晶合金液滴组织演变的数学模型,并将其与液滴的运动与传热方程相耦合,对合金的冷却凝固过程进行研究,探讨液滴尺寸对合金冷却凝固过程的影响,结合A390合金进行了计算。结果表明:随着液滴尺寸的减小,所获得的冷却速度及过冷度增大,而析出初生Si相的尺寸及体积分数减小,当液滴尺寸足够小时,液滴温度的变化趋势及微观组织将发生突变。

Based on the population dynamics model, a new model which is compiled both with droplets, heat transfer controlling equation and droplets, motion controlling equation has been developed to describe the microstructure evolution of the gas atomized eutectic alloy droplets. The effects of the droplet size on droplet cooling and solidification process of A390 alloy are discussed. The results show that with decrease of the droplet size, the quenching velocity and the degree of undercooling increase, the size and volume fraction of primary Si decrease. The thermal history and microstructure of the droplet will mutate under a critical size.