National University of Science and Technology MISIS, Moscow, Russia

А. А. Lyskovich, Postgraduate Student of the Department of Casting and Material Working, e-mail: lyskovich.aa@misis.ru
V. Е. Bazhenov, Associate Professor of the Department of Casting and Material Working, Candidate of Technical Sciences, e-mail: v.e.bagenov@gmail.com
I. I. Baranov, Postgraduate Student of the Department of Casting and Material Working, e-mail: baranov.ii@misis.ru
А. V. Кoltygin, Head of the Department of Casting and Material Working, Doctor of Technical Sciences, e-mail: misistlp@mail.ru

The main method of manufacturing cooling radiators and electronics housings of complex configuration is high pressure die casting. However, to date, most casting industrial alloys do not provide the required heat dissipation, which stimulates the demand for the creation of new lightweight casting alloys with high thermal conductivity. A promising group of alloys Al – 3% (wt.) Zn – 3% (wt.) Ca – X (where X= Si, Mg, Ni, Zr, Sc) has been studied. The effect of additives on the micro- and macrostructure of the base alloy Al – 3% (wt.) Zn – 3% (wt.) Ca has been studied by electron microscopy and energy dispersive X-ray spectroscopy. It has been shown that the addition of silicon, magnesium, or nickel leads to the coarsening of particles of the (Al, Zn)4Ca phase in eutectic. Moreover, it has been found that the addition of scandium in an amount of 0.3% (wt.) refines grains more efficiently than the addition of zirconium. Brinell hardness and thermal conductivity of alloys in the as-cast and heat-treated state have been studied (using the Smith-Palmer equation). It has been revealed that the greatest increase in hardness in as-cast alloys occurs after the addition of magnesium and silicon additives. At the same time, the addition of more than 0.1% (wt.) of the alloying element significantly reduces the thermal conductivity of as-cast alloys. Ageing at 300 оC has contributed to an increase in the hardness and thermal conductivity of scandium-containing alloys. An increase in the thermal conductivity of alloys with silicon and magnesium additives has also been noted, but their hardness remains unchanged or even decreases with increasing exposure time.
This research was supported by the Russian Science Foundation (No. 24-29-00682, https://rscf.ru/project/24-29-00682/).

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