Relationship between the nucleation and precrystallization liquid phase during homogeneous crystallization of metals

A comparative estimation of the size parameters of clusters of precrystallization liquid phase (PLP) of metals and critical crystalline nuclei has revealed the sizes of critical crystalline nuclei to be smaller than those of PLP clusters. Based on the results of estimation of the radii of critical crystalline nucleus by the methods of classical theory and molecular dynamics, it has been found for the first time that the radius of critical crystalline nucleus is about 0.2–0.4 of the PLP cluster radius. This fact confirmed the hypothesis of Ubellode et al. about the formation of a transition layer with a partially ordered structure between the solid and liquid phases. A scheme of the nucleation and growth of a crystalline nucleus under conditions of transition layer formation is proposed.