Improving the combination of electrical conductivity and tensile strength of Al 1070 by rotary swaging deformation

Abstract

In the present study, Al 1070 wires were subjected to rotary swaging (RS) with various strains at room temperature. The effect of RS on the microstructure, mechanical property and electrical conductivity was investigated by EBSD, TEM, micro hardness and tensile tests. The results showed that the grains of Al 1070 have been significantly refined and elongated during RS deformation and a fibrous structure has been formed. The elongated grains are mainly composed of sub-grains, which have a high fraction of low angle grain boundaries (LAGBs) up to 75%. Meanwhile, the volume fraction of 〈1 1 1〉 fiber texture components increased during RS processing. Due to the refined microstructure, the microhardness and the tensile property of the Al 1070 wires were increased by 54% and 70% after RS deformation at an equivalent strain of ∼2. Meanwhile, the combination of the tensile strength and electrical conductivity was improved dramatically. The electrical conductivity of the Al 1070 wires decreased gradually to 56.7% IACS from 58.6% IACS, which is only 1.9% IACS lower than the as-received one. It is proved that grain morphology of the Al wires plays a critical role in controlling the strength-electrical conductivity relation. Keywords: Aluminum, Rotary swaging, Grain refinement, Strength, Electrical conductivity