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18 February 2002 Dynamics of eutectic microstructure during phase nucleation and phase termination: phase-field model computer simulations
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Proceedings Volume 4627, Fifth International Workshop on Nondestructive Testing and Computer Simulations in Science and Engineering; (2002) https://doi.org/10.1117/12.456253
Event: Fifth International Workshop on Nondestructive Testing and Computer Simulations in Science and Engineering, 2001, St. Petersburg, Russian Federation
Abstract
Computer simulation using two-dimensional phase-field method was performed in order to observe the evolution of the composition field and the microstructure of lamellar eutectics caused by change in freezing rate. Phase nucleation, phase termination, and migration of the 3- phase junction were studied to elucidate the role of each in micro structure changes. These phenomena are complex due to the interplay between interface kinetics, the composition field, and the phase fraction. When the freezing rate is increased, the supersaturation in front of lamellae increases, causing formation of depressions, followed by nucleation, instability, and motion of the 3-phase junction. Eventually the microstructure becomes stable. With a decrease in freezing rate, instability develops that changes the local growth direction and provokes changes in lamellar width followed by elimination of some lamellae. The time scales for phase nucleation and phase termination were also estimated assuming the overwhelming importance of lateral diffusion. The model explains the time scale-lamellar microstructure parameter dependence provided that the growth rate increases with a constant acceleration, and the volume fraction does not change during an increase in the freezing rate until nucleation occurs.
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Dmitri I. Popov "Dynamics of eutectic microstructure during phase nucleation and phase termination: phase-field model computer simulations", Proc. SPIE 4627, Fifth International Workshop on Nondestructive Testing and Computer Simulations in Science and Engineering, (18 February 2002); https://doi.org/10.1117/12.456253
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