对Al-Pb合金开展了高压气体雾化快速凝固实验,金相观察表明粉末表面具有一Pb富集层.建立了描述雾化液滴凝固组织演变的数学模型,模拟分析了液滴凝固过程,结果表明,富Pb表层的形成是因为在液-液相变过程中富Pb液相在雾化液滴表面发生异质形核导致的.
High pressure gas atomization experiments were done with Al-Pb immiscible alloy. A Pb-rich shell on the alloy powder surface as observed by metaUography. A model describing the microstructure evolution in Al-Pb atomized droplet was developed. The solidification process was calculated. The results indicate that the formation of the shell-type structure is due to the heterogeneous nucleation of the Pb-rich phase on the atomized drop surface.