The ternary Cu-Co-Fe alloy was rapidly solidified by using the high pressure gas atomization technique. Powders with a well-dispersed microstructure resulting from the liquid-liquid phase transformation were obtained. A model describing the microstructure evolution in an atomized drop during the liquid-liquid phase transformation was developed. The kinetic details of the liquid-liquid phase transformation were discussed. The numerical results show a favorable agreement with the experimental ones. They demonstrate that under the rapid cooling conditions of gas atomization, the spatial phase separation due to the Marangoni migration of the minority phase droplets is very weak. Also, the effect of Ostwald coarsening of the minority phase droplets on the microstructure is negligible. For Cu-10 wt% Co-10 wt% Fe alloy, the average radius and number density of the Fe-Co-rich particles depend exponentially on the cooling rate of the melt during the nucleation period of the Fe-Co-rich droplets.
; zhao, jiu zhou] chinese acad sci, inst met res, shenyang 110016, liaoning, peoples r china.
; zhao, jz (reprint author), chinese acad sci, inst met res, shenyang 110016, liaoning, peoples r china.