Microstructure and properties of heat-resistant aluminium wire made of Al-0.4 wt.% Zr alloy copper-plated by electrochemical method

Abstract

This work examines samples of bimetallic wires with a copper sheath and a core made of Al-0.4 wt. % Zr alloy. The application of a copper layer with a thickness of 90±10 microns was carried out using the electrochemical method. Copper plating of the surface of aluminium wire leads to a decrease in the elongation to failure to 3±0.5%, while increasing the tensile strength (up to 192 MPa) and reducing the level of electrical conductivity to 57.1% IACS. Annealing at 300 °C for 1 hour leads to a twofold increase in the elongation to failure (6.3%), an increase in electrical conductivity to 62.6% IACS, as well as a slight decrease in tensile strength to the level of the original Al-0.4Zr – 176 MPa. Annealing also eliminates the staging of failure in tensile tests, which in unannealed material is caused by subsequent failure of the copper-nickel cladding and aluminium core. In terms of the totality of physical and mechanical properties, the obtained wire samples are not inferior to commercial copper-aluminium bimetallic wires. This method is promising for coating aluminium wires with a thin copper layer of controlled thickness in order to produce conductive elements in which the skin effect is realized.