Shear strain induced recrystallization/recovery phenomena within rotary swaged Al/Cu composite conductors

Abstract

The presented study aims to assess the effects of room temperature rotary swaging on structure, dynamic restoration processes in particular, within newly designed Al/Cu composite conductors. Swaging was processed from the original diameter of 50 mm (assembled billets) to the diameters of 20 mm, 15 mm, and 10 mm (final conductors). Cross-sectional samples of the swaged conductors were subjected to thorough structure analyses via electron microscopy, analyses of HV0.2 Vickers microhardness and specific electric resistivity were performed to supplement the study. Swaging to 15 mm primarily imparted structure recovery, while the final swaging to 10 mm introduced dynamic recrystallization within both the composite components (the fractions of high angle grain boundaries within Al and Cu were 78.7%, and 74.2%, respectively). The 10 mm composite Cu also featured increased fraction of Cube (Euler angles of phi 1 = 0 degrees, phi = 0 degrees, and phi 2 = 0 degrees) ideal recrystallization texture orien-tation. As regards the specific electric resistivity, this parameter was influenced primarily by accumulated dislocations, grain size and arrangement (e.g. bimodal distribution), as well as possible presence of texture. The lowest specific electric resistivity of 20.589 Omega m.10(-9) was measured for the 15 mm conductor exhibiting dynamic restoration. The Cu component of this composite also featured the highest HV0.2 Vickers microhardness value.