Neutron computed tomography of phase separation structures in solidified Cu[sbnd]Co alloys and investigation of relationship between the structures and melt convection during solidification

The effect of melt convection on the phase separation structures in undercooled Cu[sbnd]Co alloys was investigated using the electromagnetic levitation technique, where the melt convection was controlled by applying a static magnetic field. The three-dimensional phase separation structures of the solidified Cu[sbnd]Co alloys were first observed using neutron computed tomography. A large number of small spherical Co-rich phases were dispersed in the Cu-rich phase matrix when the static magnetic field was relatively small. In contrast, several coalesced Co-rich phases, which were elongated along the direction of the static magnetic field, appeared in the higher strength of static magnetic field.