"Nucleation When Diffusion Becomes Important: A Tale of Two Fluxes"


Professor Ken Kelton , Department of Physics - Washington University
[Host: Joseph Poon]
ABSTRACT:
The classical theory of nucleation does not properly describe nucleation processes when long-range diffusion becomes competitive with the interfacial processes. A new model is presented for time-dependent homogeneous nucleation in condensed phases, which takes account of the coupled fluxes of interfacial attachment and long-range diffusion. Numerical solutions from this new model show that the time-dependent nucleation rates scale with the dominant mobility and that the steady-state rates and induction times frequently differ significantly from values predicted by the classical theory. Surprisingly, the composition of the region of the parent phase near sub-critical crystal clusters is shifted toward that of the new phase. Consequences are discussed for solid state precipitation and the crystallization of Al-rare earth metallic glasses.
Condensed Matter Seminar
Thursday, October 12, 2000
4:00 PM
Physics Building, Room 204
Note special time.
Note special room.

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