  Solidification pattern during nonequilibrium crystallization is among the
most important microstructures in the nature and technical realms. Phase field
crystal (PFC) model could simulate the pattern formation during equilibrium
crystallization at atom scale, but cannot grasp the nonequilibrium ones due to
the absence of proper elastic-relaxation time scale. In this work, we propose a
minimal classical-density-functional-theory-based model for crystal growth in
supercooled liquid. Growth front nucleation (GFN) and various nonequilibrium
patterns, including the faceting growth, spherulite, dendrite and the
columnar-to-equiaxed transition (CET) among others, are grasped at atom scale.
It is amazing that, except for undercooling and seed spacing, seed distribution
is key factor that determines the CET. Overall, two-stage growth process, i.e.,
the diffusion-controlled growth and the GFN-dominated growth, are identified.
But, compared with the second stage, the first stage becomes too short to be
noticed under the high undercooling. The distinct feature for the second stage
is the dramatic increments of dislocations, which explains the amorphous
nucleation precursor in the supercooled liquid. Transition time between the two
stages at different undercooling are investigated. Crystal growth of BCC
structure further confirms our conclusions.
