Application of fractal theory on the study of solid-liquid interface morphology

摘要

The solidification process of an alloy is a compli-cated phenomenon, involving heat transfer, solute redistribution and fluid flow, all of which are closely related with interface dynamics. The morphology and evolution of a solidification interface have been the key problems in the solidification research field. For many years the morphology of the solid-liquid interface Was described only qualitatively by means of microscopy, which gives many problems in having a deep understanding because of a lack of a quantitative base. In recent years fractal geometry lias attracted many scientists working in various research fields and much work has been done [1-3]. Hidden laws and physical mechanisms inside complicated phenomena have been found by means of the fractal method. However, it is still a problem whether the morphology of the solid-liquid interface morphology can be described quantitatively by the new fractal method and there has been a lack of reports in this field up to now. This letter, starting with a fractal definition, demonstrates that the morphologies of the solid-liquid interface in a directionally solidified alloy are certain kinds of irregular fractal structures and tries to introduce the new method of fractal analysis into the study of the solidification behaviour.