  A thorough understanding of pattern selection is necessary for the control of
solidification structures, which are dissipative structures created by
irreversible processes. In this paper, we simulate solidification evolution
with different Preferred Crystallographic Orientations (PCOs) through the
Phase-Field model. Then we study the effect of solute segregation on the
interface energy, as well as the influence of the interface energy on the
pattern selection. At the initial stage, the solute segregation influences the
interface energy, determining the instability of the planar interface. During
the detailed evolution of the Planar-Cellular-Transition (PCT), the surface
stiffness dominates this stage. At the PCT stage, high degree of solute
segregation refers to the low interface energy, resulting in the appearing of
the sidebranches behind the tip of the primary dendrites. At the steady-state
stage, the overall propagation velocities of the interfaces are the same, while
the tip velocities are different in the simulations with different PCOs. The
different tip velocities give rise to the different morphological evolution of
the interfaces. The viewpoints of the whole dissipative system and the local
free energy are discussed, respectively. This paper demonstrates the effect of
solute segregation on the interface energy, as well as the influence of the
interface energy on the pattern selection.
