HEREDITARY INFLUENCE OF MELT PROCESSING ON THE THERMAL EXPANSION OF ALUMINUM IN THE SOLID STATE

10.25712/ASTU.1811-1416.2026.02.012

Abstract

The paper reflects the results of experimental studies of the possibility of reducing the temperature coefficient of linear expansion (TCLE) of technical grade A7 aluminum by melt treatment, which can be considered as microalloying.

The effect of complex modification, i.e. the combined treatment of aluminum melt with calcium carbonate and additives of various components, such as silicon, copper, and silicon oxide, on the structure and thermal expansion of aluminum, has been studied.

It has been demonstrated that, without the introduction of alloying elements, by treating the melt with a mixture of alkaline earth metal carbonates, it is possible to significantly reduce the TCLE of technical-grade aluminum in the instrumentation temperature range to values ​​characteristic of Al–20% Si alloys. It has been established that combined treatment of the melt with alloying element oxides and calcium carbide provides the greatest reduction temperature coefficient of linear expansion in over the entire test temperature range compared to separate alloying and treatment of the CaCO₃ melt. These results can be used to produce lightweight alloys with controlled thermal expansion.