Improvement of mechanical and electrical properties of rotary swaged Al-Cu clad composites

Publication date: 5 June 2017
Source:Materials & Design, Volume 123
Author(s): Radim Kocich, Lenka Kunčická, Adéla Macháčková, Michal Šofer
In order to investigate modifications in electric resistivity, mechanical properties and structures of Al/Cu clad composite induced by various thermomechanical-treatments, work-pieces were swaged under two temperatures (25°C and 250°C) to three final diameters (10, 7.5 and 5mm) and subsequently subjected to two different heat treatments. The influence of the two swaging temperatures on formability of the clad composites was evaluated via tensile and bending tests with integrated detection of acoustic emission. The highest tensile strength (~500MPa) was recorded after semi-final swaging for both the composites. The strain imposed during the gradual swaging process significantly influenced hardness of both the metals within the composites, the development of which was non-linear. Structure analysis proved restoration processes in Cu to occur during swaging to 5mm at 25°C, however, at 250°C restoration occurred already during the last but one pass to 7.5mm. Heat treatment introduced further structure changes; the annealing temperature of 350°C also resulted in the development of an intermetallic layer on the Al/Cu interfaces, which also contributed to decreases in mechanical properties. Results of electric resistivity measurements showed all the composites to have higher conductivity than Al work-pieces swaged via the identical procedures.

Graphical abstract

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