  This paper investigates the behaviour of colloidal suspensions of alumina
particles during directional solidification, by in situ high-resolution
observations using X-ray radiography and tomography. This second part is
focussed on the evolution of ice crystals during steady state growth (in terms
of interface velocity) and on the particles redistribution taking place in this
regime. In particular, it is shown that diffusion cannot determine the
concentration profile and the particles redistribution in this regime of
interface velocities (20-40 microns/s); constitutional supercooling arguments
cannot be invoked to interpret particles redistribution. Particles are
redistributed by a direct interaction with the moving solidification interface.
Several parameters controlling the particles redistribution were identified,
namely the interface velocity, the particle size, the shape of the ice crystals
and the orientation relationships between the crystals and the temperature
gradient.
