Peter the Great St. Petersburg Polytechnic University, Saint Petersburg, Russia:

G. A. Kosnikov, Professor

A. V. Kalmykov, Researcher

Grozny State Oil Technical University, Grozny, Russia:

A. S. Eldarkhanov, Chief Executive Officer, e-mail: chief@nomit.ru

LLC “Kriamid”, Moscow, Russia:

V. V. Serbin, Chief Executive Officer

Transformation of dendritic structure of alloys into non-dendritic one provides the significant improvement of mechanical properties of the alloys at different casting methods. Ultrasonic treatment is one of the most efficient methods of external influence on dendritic structure of alloys, while aluminum alloys are the most widely used objects of study. At the same time, various ultrasonic equipment is used together with temperature ranges and duration of ultrasonic treatment, and methods of ultrasound introduction into the melt. The influence of ultrasound on alloy AK7 solid solution dendrites was investigated as a result of its cooling from liquid state and heating from solid to liquid-solid state, changing of temperature ranges and the influence duration. There was defined the ultrasonic treatment mode, making the highest influence on solid solution dendrite degeneracy during the cooling of the melt, reheated on liquidus to the solid-liquid state. There was carried out the assessment of influence of utlrasonic treatment on heat effects in the waveguide-melt-crucible system. There was also carried out the analysis of the nature of thermal curves and efficient ultrasonic treatment modes, conductive to thixostructure formation. There was made a research of influence of heating duration of initial charge to liquid-solid state on dendritic structure formation. The nature of dendritic structure evolution during sequential thermal-time and ultrasonic treatments was defined. There was made a conclusion about the highest ultrasound efficiency during the alloy treatment in liquid-solid state, preservation of hereditary features of degenerated dendritic structure of alloy (charge) during the reheating to liquid-solid state.

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