The Precipitate-Nucleation in the Vicinity of Solubility Limit
The critical minimum size of stable precipitate in the vicinity of edge of miscibility gap is experimentally determined for the Ni3Si precipitate particle in Ni-Si, Ni3Al in Ni-Al, Cu4Ti in Cu-Ti and Co in Cu-Co binary alloy systems by utilizing the macroscopic composition gradient method recently proposed. The results obtained are as follows: The critical nucleus size shows a rapid increase to several tens of nm in a very narrow composition region less than 0.3at% from the phase boundary. Such a big critical size of nucleus is statistically rationalized by the conventional nucleation theories.
Masaaki Naka and Toshimi Yamane
T. Miyazaki et al., "The Precipitate-Nucleation in the Vicinity of Solubility Limit ", Materials Science Forum, Vol. 502, pp. 139-144, 2005