Cu-Cnts Composite Foils with Twinning-Induced High Ductility

Abstract

Copper foils typically display low ductility and are prone to rupture under high strains. Although various plastic deformation methods can improve their malleability, they are often uneconomical for mass production. This study aims to enhance copper foil ductility by integrating carbon nanotubes (CNTs) and annealed twins. The results demonstrate that the introduction of CNTs increases the dislocation density in electrolytic copper foils, boosting strain hardening capabilities. The grain growth that occurs following low-temperature annealing, coupled with the enhancement of the twin boundary density with high geometric compatibility factor (m') values, facilitates improved slip transfer. The resulting 9 μm thick annealed Cu-CNTs composite foils now demonstrate superior mechanical properties, with an elongation of up to 16.5%, compared to conventional copper foils.

Keywords: Copper foil, Cu-CNTs, annealing, Twin boundary, Ductility