Study of changes in microstructure and metal interface Cu/Al during bimetallic construction wire straining

This article investigates the effect of a new processing technology on the change in microstructure and mechanical properties of bimetallic aluminum-copper wire. This technology makes it possible to produce a new generation of wire for use in the construction of new overhead lines and reconstruction of old ones. The study was conducted using a transmission electron microscope, EBSD analysis, tensile tests, and determination of microhardness and electrical conductivity. The results of the study show that an ultrafine-grained copper-aluminum composite with a gradient structure is formed during straining by ECAP-drawing. Annealing after straining at 200 °C increases the strength of the interfacial connection between Cu and Al and improves the strength characteristics of the bimetallic aluminum-copper wire. The use of such aluminum-copper wires for overhead transmission lines allows to reduce the wire cross-section and, accordingly, wind loads, as well as to increase the strength properties without an additional increase in the total weight of the wire.