Modern nanostructured metal conductors for wires and cables with increased conductivity and improved strength properties
The use of pure metals having high electrical conductivity is impossible because of their low strength. An increase in the strength of a metal due to its alloying by traditional methods for producing alloys leads to the inevitable loss of electrical conductivity due to the scattering of electrons by impurity atoms, the precipitation of new phases, and other defects that arise during the manufacturing of the alloy. One of the possible methods to creating materials with a combination of high strength and high conductivity is creating a special microstructural design using severe plastic deformation methods (such as severe plastic deformation by high-pressure torsion and equal channel angular pressing) of metal alloys based on aluminum and copper in combination with their subsequent heat treatment. Severe plastic deformation leads to the formation of an ultrafine-grained structure of the alloy, in the process saturating it with grain boundaries in a special state that differs from the state of grain boundaries in
coarse-grained materials. Subsequent heat treatment can achieve the optimal phase composition of the intragrain material and composite structure of the grain boundaries due to the separation of clusters of impurity atoms on them. The heterogeneous structure formed in this way has increased strength properties due to grain refinement and the presence of precipitates of new phases both inside the grain and along grain boundaries and increased electrical conductivity due to a decrease in the concentration of impurity atoms in the solid solution of the intragrain phase.
In the field of developing fundamentally new nanostructured metal conductors, there is close cooperation between the center’s team and research groups from The Institute of Physics of Advanced Materials of the Ufa State Aviation Technical University and St. Petersburg State University under the guidance of prof. R.Z. Valiev, a leading scientist in Russia and the world in the field of physical metallurgy and bulk nanostructured materials. Since 2019, together with the University of Rouen Normandie (Prof. W. Lefebvre), joint studies of the fine structure of grain boundaries have been started using advanced techniques in microscopy. The aim of studies are identifying key microstructural parameters that control the strength properties and electrical conductivity of aluminum alloys in ultrafine-grained state, as well as related features of hardening mechanisms and electron scattering mechanisms in ultrafine-grained structures, which is an important and urgent task of physical materials science.