Nonequilibrium Interface Dynamics:
Fundamental Physical Issues in Nonequilibrium Interface Dynamics

CSIC Building (#406), Seminar Room 4122.
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Interfacial Boundary Conditions and Phase-Field Models of Solidification

Dr. Geoffrey McFadden

Mathematical and Computational Sciences Division, NIST

Abstract:   Phase-field models of solidification treat phase boundaries as diffuse interfaces, rather than mathematically sharp surfaces of zero thickness. The diffuse interface is described by contours of a non-conserved order parameter, and the dynamics of interface motion is governed by an auxiliary equation derived from a free-energy functional that contains both gradient energy terms and bulk free energies. Sharp-interface boundary conditions may be recovered from diffuse interface models in appropriate limiting cases, and can provide an alternate approach to deriving non-equilibrium interface boundary conditions. Phase-field models have been developed in a variety of contexts, including the effects of multicomponent diffusion, hydrodynamics, electrodeposition, and elasticity. Some examples of equilibrium and non-equilibrium boundary conditions obtained in this manner will be presented.