  The slow non-monotonic relaxation processes, which have been recently fixed
in Al-Y melts, are described theoretically. The theoretical description is
based on the Cahn-Hilliard theory and functional methods of non-equilibrium
dynamics. In terms of the suggested approach the reasons of this relaxation
kinetics are non-linearity of the system near to the liquidus line, which
sharply increases with Y concentration, and strong initial heterogeneity of the
melt on the concentration of Y atoms. According to our analysis one can
conclude that the non-monotonic temporal dependence of viscosity is caused by
the Ostwald ripening processes in the rich in yttrium areas.
