Saint Petersburg State Polytechnical University, Saint Petersburg, Russia:

Kazakov A. A., Professor, Head of a Chair of Metallurgical Technologies
Kiselev D. V., Engineer (Chair of Metallurgical Technologies)
Kur A. A., Post-Graduate Student (Chair of Metallurgical Technologies), e-mail: kur@thixomet.ru

Research Center of “Avtovaz” JSC, Tolyatti, Russia:

Lazutova E. B., First Category Research Engineer

Quantitative methods for evaluation of microstructure of hypoeutectic aluminum-silicon alloys were developed and implemented as a plug-in of image analyzer Thixomet PRO. Unmodified and processed AK6M2 and AK10M2N alloys were investigated, which made possible to obtain various degree of fi neness of Al – Si eutectic, which covered all classes of modifi cation in accordance with the standard bar chards of American Foundry Society (AFS). Coefficient of eutectic fi neness of these alloys was developed: the average distance between all pixels, located within the particles to their boundaries, was calculated at the binary image of silicon particles. The reciprocal of this average distance is called a coefficient of eutectic fineness and describes all classes of modification in accordance with the standard bar chards of AFS. Regression equations were calculated. They adequately describe the mechanical properties of investigated cast alloys, based on the developed coeffi cient of eutectic fi neness and volume fractions of porosity and coarse intermetallic inclusions (greater than 5 micron), evaluated by usage of ASTM E 1245. For the purpose of interpretation of nature of the phases, found by microprobe analysis, thermodynamic modeling was applied, using FactSage software, powered by SGTE databases. There were designed the nomograms, illustrating the effect of each of the studied parameters of the structure on mechanical properties of AK6M2 and AK10M2N alloys. Developed methods for forecasting of hypoeutectic aluminum-silicon alloys' properties by their structure can be used in their production for quality control during acceptance tests.

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