Abstract: Liquid separation of Cu75Co25 and Cu85Co15 alloys at various supercoolings was investigated employing glass flux technology. The results reveal that during the course of isothermal processes, liquid separation develops more fully than in the continuous cooling, which results in more and larger particles. Further thermodynamic analyses indicate that primary dendrites from liquid separation are inclined to remelt in Cu liquid and finally the dendrites shrink locally, or even break into fragments. The fragments clash each other and grow into larger Co-rich particles due to electromagnetic force. It is also showed that at constant temperature whether Co-rich particles solidify depends on the develop level of the liquid separations. Co-rich liquid droplets begin to solidify when the component of Co-rich liquid reaches the solidus.

Key words:  Cu-Co alloys; liquid separation; supercooling; solidification