Formation of theShell-type Structure in a Powder of Al-Pb Alloy
Al-Pb合金粉末壳型组织形成过程

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.