ANALYSIS OF THE EFFECT OF EXTERNAL PHYSICAL FIELDS ON THE CASTING OF LIGHT ALLOYS

Advanced methods of external physical effects on the aluminum alloys during casting process and addition of reinforcing elements, which are used in the Research Laboratory of High-Energy and Special Materials in Tomsk State University, are analyzed. These methods are mechanical stirring, treatment by electromagnetic fields, vibration, and ultrasound. Application of external fields leads to an increase in the performance of obtained alloys by means of degassing, decreasing in the average grain size, increasing in the uniformity of alloy structure, decreasing in the quantity of agglomerations and impurities on the grain boundaries, improving wettability, etc. The changes observed in the structure of melt and the dependence of melt properties on the type and treatment mode of the external field, on the characteristics of initial metal as well as on the characteristics and quantity of reinforcing particles added to the melt are shown. The results of several experiments demonstrating the effect of external fields on the aluminum alloys during casting process and the impact of reinforcing particles added to the melt are presented. The diagrams of technological installations whereby the external fields impact the melt are shown. The main parameters of operating conditions of installations are identified; for mechanical mixing they are the impeller rotation rate and the duration of mixing; for treatment by electromagnetic fields - the current intensity, the voltage frequency, and the exposure time; for ultrasound treatment - the capacity, the magnitude and the frequency of ultrasound, and the duration of application; for vibration - the frequency, the amplitude, and the duration of vibration.