Al基难混溶合金快速定向凝固研究 Ⅲ.第三组元的影响

INVESTIGATION OF RAPID DIRECTIONAL SOLIDIFICATION OF Al-BASED IMMISCIBLE ALLOYS Ⅲ.Effect of the Third Element

对Al-Bi基难混溶合金添加第三组元Si和Cu,揭示了Si和Cu含量对Al-Bi合金快速定向凝固组织的影响．结果表明,添加Si或Cu均使凝固组织中的富Bi粒子尺寸增大;在相同的实验条件下。元素Si比Cu更易使富Bi相粗化．分析了第三组元对二元合金体系的自由能、两液相间界面能和液相粘度的改变及其对合金凝固过程的影响,加深了对三元难混溶合金凝固特征的认识．

The directional solidification experiment has been carried out for the Al-Bi based immiscible alloys. The effect of the addition element Si or Cu on the solidification microstructnre was investigated. The results show that both Si and Cu accelerate the coarsening of the Bi-rich particle, and the effect of Si is more obvious than the element Cu under the same experimental condition. The changes of the free energy, liquid-liquid interracial energy and liquid viscosity due to the addition have been analyzed. Also, the effect of the above changes on the solidification process was discussed in detail. This investigation will enrich the understanding of the solidification feature of the ternary immiscible alloys.