Microstructures Of Rapidly Solidified Cu--Fe Immiscible Alloy
快速凝固Cu-Fe难混溶合金的显微组织

Fine powders of the Cu-Fe alloy were manufactured by using the high-pressure gas atomization technique. The study of the powder microstructures indicated that the size and concentration of the atomized-droplets play important roles in the microstructure evolution. A smaller atomized-droplet has a finer dispersed microstructure. Alloys with composition close to the critical composition of the alloy system are relatively easy to be undercooled into the miscibility gap. The formation of Fe-poor layer on the surface of powder is mainly caused by two reasons. One is the Fe-rich droplets' Marangoni migration towards the center of the atomized-droplet due to the radial temperature gradient, and the other is the repulsive effect of the advancing solid/liquid interface on the Fe-rich droplets.