Analysis of Spatial Structures Arising During Eutectic Crystallization and Cellular Decomposition of Solid Solutions
M. O. Ivanov, A. Yu. Naumuk
G.V. Kurdyumov Institute for Metal Physics, NAS of Ukraine, 36 Academician Vernadsky Blvd., UA-03680 Kyiv-142, Ukraine
Received: 18.11.2014. Download: PDF
The conditions for occurrence of different structures during stationary processes of eutectic crystallization and cellular decomposition of supersaturated solid solutions are analysed. This discussion is based on a previously proposed approach, which is composed of a comparison of the rates of change of free energy calculated by two different methods and a certain variational principle to choose between different ways of implementing such processes. It turns out that the most advantageous under given external conditions is such a structure, for which the minimum value is achieved for product of the total value of surface energy related to the formed phases on the structure factor of the process, which arises under this approach. Besides, the form of the structure factor depends essentially on the mechanism for the implementation of the separation (bulk or surface) diffusion. Based on such considerations, comparison of the lamellar and rod structures arising during eutectic crystallization and cellular decomposition of solid solutions is carried out. For a rod structure, various types of rods’ arrangements over a two-dimensional lattice are considered, namely, with the regular triangular or rectangular cells, and certain rod cross-section facetings different from circular one, for instance, in the form of regular hexagon, are also considered.
Key words: stationary non-equilibrium processes, eutectic crystallization, cellular decomposition of supersaturated solid solutions, lamellar structure, rod structure, diffusion, the rate of change of free energy.
PACS: 64.60.A-, 64.60.My, 64.70.dg, 65.40.gd, 65.40.gp, 66.30.Fq, 81.30.-t
Citation: M. O. Ivanov and A. Yu. Naumuk, Analysis of Spatial Structures Arising During Eutectic Crystallization and Cellular Decomposition of Solid Solutions, Metallofiz. Noveishie Tekhnol., 36, No. 12: 1571—1596 (2014) (in Russian)