Optimizing structure and properties of Al/Cu laminated conductors via severe shear strain

Abstract

The study is focused on determining the relations between electric properties and structural features within newly designed laminated Al/Cu conductors manufactured via rotary swaging at room temperature and subjected to two post-process heat treatments. Structure analyses were performed via scanning and transmission electron microscopy, mechanical properties were investigated via microhardness measurements, and electric properties during direct and alternating current transfers were both experimentally examined and numerically simulated. Fabrication of the laminate via rotary swaging introduced advantageous combinations of electric and mechanical properties, the design of the laminate had favourable effect on decreasing power losses during alternating current transfer, too. Specific electric resistivity was affected particularly by structural features, such as grain size, grain boundaries and twinning, and texture orientations and intensity. The lowest specific electric resistivity (22.7 Ωm×10−9) was measured for the swaged laminate heat treated at 350 °C featuring structure restoration. Annealing at 250 °C imparted partial structure restoration resulting in bimodal grain size distribution and substantial deterioration of the electric properties.