PHASE FIELD FORMULATIONS FOR MODELING THE OSTWALD RIPENING IN 2-PHASESYSTEMS

Phase field formulations have been constructed for modeling Ostwald ri pening in two-phase systems. The microstructural evolution and the kin etics of Ostwald ripening were studied by numerically solving the time -dependent Ginzburg-Landau (TDGL) equations. The simulated microstruct ures are in a striking resemblance with experimental observations. The shape accommodation of second phase particles occurs as the volume fr action increases. It was observed that these two-phase systems reach t he steady state or scaling state after a short transient time and the scaling functions are independent of time for all volume fractions of the second phase. The kinetics of Ostwald ripening in a two-phase mixt ure have been studied over a range of volume fractions of the coarseni ng phase. It was found that the coarsening kinetics of second phase pa rticles follows the power growth law R-t(m) - R-o(m) = kt with m = 3, which is independent of the volume fraction of the coarsening phase. T he kinetic coefficient k increases significantly as the volume fractio n of the coarsening phase increases. (C) 1998 Published by Elsevier Sc ience B.V.