National University of Science and Technology “MISiS”, Moscow, Russia:

N. A. Belov, Professor, Director of Engineering Center “Casting Technologies and Materials”, e-mail: nikolay-belov@yandex.ru
N. O. Korotkova, Post-Graduate Student of Casting Process Technology Chair
Т. K. Akopyan, Researcher of Engineering Center “Casting Technologies and Materials”

Kazakh National Technical University named after K. Satpaev, Almaty, Kazakhstan:

A. M. Dostaeva, Doctoral Student of a Chair of Machine-Tool Construction, Material Science and Mechanical Facilities Technology

In the last years, power engineering has been stably interested in aluminium alloys, having high electroconductivity and sufficient durability, remaining after heating up to the temperature of 250–300 °С. Traditional wires, made of technical aluminium А5Е and А7Е, do not fulfill theese requirements because of their strong softening even after short-time heating to such temperatures. Creation of wire, made of low aluminium alloy with zirconium addition, is the most prospective way of this problem solving. The increased high-temperature durability of these alloys is provided due to the secondary isolations of Al₃Zr phase, which sizes are ~10 nm. The electrical resistivity of aluminiunm is significantly increased by zirconium in aluminium solid solution. According to this, annealing is required for maximal decrease of Zr concentration in aluminium solid solution, and, on the other hand — for the formation of the required amount of Al₃Zr phase nanoparticles. There was researched the influence of thermomechanical treatment modes on specific electrical resistivity and hardness of two aluminium alloys (cold rolled and hot rolled ignots and sheets, containing 0.2 and 0.4% Zr). There was made a definition that the slowest decomposition of solid Al solution is in ignots, and the fastest one is in cold-rolled sheets. Desirability function application shows that the best combination of values of specific electrical resistivity, hardness and softening resistance can be reached in cold-rolled sheets, made of alloy 0.4% Zr, annealed at the temperature of 450 °C. This combination of properties is mainly substantiated by formation of a sufficient number of Al₃Zr phase nanoparticles, which define the strain hardening saving.
This article was written in the context of the Agreement No. 14.578.21.0039 (unique identifier of the project is RFMEFI57814X0039) for the subsidy of Ministry of Education and Science of Russian Federation in the context of the Federal Target Program “Research and development of priority ways of development of scientific-technological complex of Russia for 2014–2020”.

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