Samara State Technical University, Samara, Russia:

R. M. Biktimirov, Assistant Lecturer at the Department of Foundry and High- Efficiency Technologies, Engineer, e-mail: r.biktimirov1995@gmail.com
I. Yu. Timoshkin, Associate Professor at the Department of Foundry and High-Efficiency Technologies, Candidate of Technical Sciences, e-mail: ivan-mns@mail.ru
K. V. Nikitin, Dean of the Faculty of Mechanical Engineering, Metallurgy and Transport, Doctor of Technical Sciences, Professor, e-mail: kvn-6411@mail.ru

This paper describes the results of a study that looked at the effect of the structure of AlSi20 and AlTi5 master alloys on the structure and physico-mechanical properties of alloy AK9ch (Al – Si – Mg system). It is demonstrated that due to the use of mould for processing of master alloy melts (solidification in a water-cooled roller mould), microdispersed phases get formed in the master alloy structure: primary silicon crystals Siп (in AlSi20) and intermetallides Al3Ti (in AlTi5). The paper examines the effect of the AlTi5 master alloy on the structure and physico-mechanical properties of the AK9ch alloy produced by using coarse-crystalline and microcrystalline master alloys. It was found that the partially modified structure of the AK9ch alloy can be obtained avoiding using the AlTi5 master alloy when using microcrystalline AlSi20 master alloy as the basis. The experiments that were aimed at understanding the relationship between the master alloy structure and the modification capacity of the alloy showed that the structure of the AlSi20 and AlTi5 master alloys produces a hereditary effect on the structure and physico-mechanical properties of the AK9ch alloy. Optimum parameters in terms of structure, gas content and physico-mechanical properties were achieved in the alloy produced with the help of microcrystalline AlSi20 and AlTi5 master alloys. However, this required introduction of 0.02%(wt.) Ti. When using coarse-crystalline master alloys, 0.06%(wt.) Ti should be introduced for optimum parameters to be achieved. By using microcrystalline master alloys for alloy preparation, one can achieve a triple reduction in the consumption of the high-cost AlTi5 master alloy without compromising the physico-mechanical properties. The established effects can be well explained from the point of view of the key regularities of structural heredity.

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