National University of Science and Technology "MISIS" (MISiS)

M. A. Ryazantseva, Post-Graduate Student, e-mail: riazantseva@misis.ru

A. N. Solonin, Head of a Chair

V. K. Portnoy, Professor of a Chair of Metallography of Non-ferrous Metals

The search for new heat-resistant alloys with the high electrical conductivity for wires of electric power lines is very actual task. The Al – Mg – Si-alloys, used for preparing the current-carrying lines, possess the necessary electrical conductivity but suffer from softening at elevated temperatures. Our study is devoted to development and optimization of the aluminum alloys with high resistance of mechanical properties to heating combined with high electrical conductivity for electric power lines. The purpose of the work is the study of the influence of microalloying on electrical conductivity and stability of the dislocation structure (reduction of the softening) of the cold-deformed alloys with the heating, including in the extreme conditions. Present article is focused on the study of the kinetics of the softening with heating of the aluminum binary dilute alloys and on the influence of the small concentrations of the alloying elements on the electrical conductivity. In the work the analysis of the influence of small additions Zn, Mg, Ag, Cu, Ti, Fe, Cr, Mn, Si and Zr is carried out. It is shown that the reason of Zn-containing alloy softening at heating is polygonization. Magnesium provides the best resistance to softening among other soluble elements. Among additions forming intermetallic phases the most effective is iron if concentration of alloying element is 0.05% or zirconium at higher concentrations. In the range of studied concentrations all soluble additions decrease aluminum electroconductivity less than on 5%. The additions forming intermetallic phases decrease electroconductivity up to 50%.

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