  Cr-segregation to a lamellar interface in NbSi2/MoSi2 duplex silicide has
been examined by a newly developed phase-field model. The model can take into
account the segregation energy evaluated by a first principles calculation to
reflect the chemical interaction between solute atoms and the interface in
addition to the elastic interaction. Cr segregation occurs at the interface in
the case with segregation energy whereas no segregation occurs in the case with
only elastic interaction. However, the segregation is much smaller than that
observed in the experiment when the segregation energy was evaluated by the
first principles calculation without lattice vibration (i.e. for 0 K). Another
simulations with the segregation energy with lattice vibration results in
segregation comparable to that in the experiment. Thus, it has been revealed
that the solute-interface chemical interaction and its temperature dependence
is responsible for the interfacial segregation of Cr.
