Comparison of Phase Separation Structures between Undercooled Cu–Fe and Cu–Co Alloys Solidified Under a Static Magnetic Field

An electromagnetic levitation technique superimposed with a static magnetic field was used to investigate the effects of the convection and cooling rate of levitated molten Cu80Fe20 alloy on the size and morphology of induced phase separation structures formed during undercooling. The obtained results were compared to our previous works on the Cu80Co20 alloy, in terms of the size and morphology of the phase-separated structures of dispersed Fe-rich phases. It was revealed that the Sauter mean diameter in the two systems followed the same trend, although the Co-rich phases were larger in size than the Fe-rich ones at higher static magnetic fields. Under a larger static magnetic field, the separated Co-rich phases in Cu–Co alloys had an elongated shape along the direction of the static magnetic field, while the Fe-rich phases in Cu–Fe remained almost spherical in shape. This difference in shapes was attributed to physical properties, particularly their magnetic susceptibility.