¹Institute of Continuous Medium Mechanics of Ural Branch of Russian Academy of Sciences, Perm, Russia; ²Perm National Research Polytechnic University, Perm, Russia:

S. Yu. Khripchenko^1,2, Professor, Leading Researcher

Institute of Continuous Medium Mechanics of Ural Branch of Russian Academy of Sciences, Perm, Russia:
L. V. Nikulin, Senior Researcher
V. M. Dolgikh, Senior Researcher
S. A. Denisov, Senior Researcher

The paper is concerned with the study of influence of rotating magnetic field on structure and properties of small-sized aluminum-silicon ingots. Structure of ingots, subjected to MHD-stirring, was compared with the structure of ingots, which were not treated by magnetic field. Macrostructure of nontreated ingot consists of large dendrites with first-order elongated axis (dendrite trunk) and eutectics. Application of magnetic field changes the morphology of dendrites: a compact grain occurs on dendrite trunk place. This grain is surrounded by volume “cluster” of secondary branches which look like a set of subgrains (sectional view). The most pronounced visible changes in microstructure are related to silicon phase in eutectic component. Silicon plates in this component are transformed into separate inclusions in aluminum solid solution matrix. Thus, under the action of rotating magnetic field, there happens the elimination of large-sized dendritic structure; changing of dendrites morphology and corresponding grinding of macrostructural grains by 2–2.5 times. At the same time, modifications of microstructure are changed: secondary branches of dendrite assume a rounded shape, and plate-like shape of silicon phase in eutectic components assumes the shape of compact isolated inclusions. Processing in magnetic fields is an efficient way to controlling of ratio of ingot structural components with no changes in alloy composition. Structural parameters are controlled by changing of induction magnitude of rotating magnetic field. It was experimentally found that MHD-stirring of alloy during its solidification in crucible allows to create the ingot structural state, required for final operations of forging, pressing and hardliquid molding with further thermal processing of finished products.

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