Simulation of Supercooling Solidification by Phase Field Model.

Abstract

Numerical simulation of supercooling solidification was conducted by phase field model (PFM) derived consistently to thermodynamics to clarify a mechanism of dendritic crystal growth. Solid and liquid states are identified in the model by phase variable, which changes continuously over interfacial region. The PFM is composed of heat conduction equation with a source term of latent heat and phase equation including surface tension effect, nonequilibrium effect by supercooling and kinetic solidification speed. The derived model can quantitatively reproduce Gibbs-Thomson effect and morphological instability of solid-liquid interface during supercooling solidification. Dendritic solidification was also simulated by considering surface tension, nonequilibrium and anisotropy based on crystal structure in atomic scale. Various pattern formations in solidification were studied through the PFM by changing conditions such as surface tension, degree of supercooling and anisotropy. It is expected that the PFM entirely explain physical behavior of supercooling solidification and mechanism of dendritic pattern formation.