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建立了偏晶合金连续凝固过程的群体动力学模型,并将其与传热、传质和流场控制方程相耦合,对Al-Pb偏晶合金连续凝固过程进行了模拟,分析了凝固速率、合金成分和熔炼温度等对合金连续凝固组织形成过程的影响.结果表明:凝固速率越大,凝固界面前沿弥散相液滴的形核位置越靠近凝固界面,弥散相液滴的形核率和数量密度越大,平均半径越小.越有利于获得弥散凝固组织;合金Pb含量越高,凝固界面前沿弥散相液滴的形核位置越远离凝固界面,弥散相液滴的形核率越低,平均半径越大,越不利于获得弥散凝固组织.熔炼温度越高,弥散相液滴的数量密度越大,平均半径越小,有利于获得弥散组织;但随熔炼温度提高,液滴的综合运动速度逐渐降低,该速度降为负值时,合金不能实现稳态凝固,导致偏析组织的形成.
The group dynamics model of the continuous solidification process of the monotectic alloy was established and coupled with the governing equations of heat transfer, mass transfer and flow field. The continuous solidification process of Al-Pb monotectic alloy was simulated. The solidification rate, The results show that the larger the solidification rate is, the closer the nucleation sites of dispersed phase droplets are to the solidification interface and the nucleation rate and number of dispersed phase droplets The larger the density is, the smaller the average radius is, the more conducive to obtaining the dispersed solidified microstructure. The higher the content of Pb in the alloy, the finer the nucleation position of the dispersed phase droplets at the front of the solidified interface farther away from the solidified interface, The larger the average radius is, the harder it is to obtain the dispersed solidified structure.The higher the melting temperature, the larger the number density of dispersed phase droplets and the smaller the average radius are, the better the dispersion structure is obtained. However, with the increase of melting temperature, When the velocity decreases to negative value, the alloy can not achieve steady state solidification, resulting in the formation of segregation structure.