Microstructure evolution during a liquid-liquid decomposition under the common action of the nucleation, growth and Ostwald ripening of droplets

Abstract

The kinetic details of the microstructure evolution during a liquid-liquid phase transformation under the common action of the nucleation, the diffusional growth and the Ostwald ripening of the minority phase droplets are investigated numerically. The results demonstrate that the cooling rate during the nucleation period of the minority phase droplets has an overwhelmingly strong effect on the microstructure formation compared with the cooling rate after the nucleation period. Generally, the effect of the Ostwald ripening of the droplets is very weak in an alloy cooled continuously all through the miscibility gap. An obvious coarsening of the droplets occurs only when the cooling rate decreases by more than two orders of magnitude after the nucleation of the precipitated droplets.