Strength-conductivity synergy in cold-drawn reduced graphene oxide (RGO)-aluminum composite wires for electrical applications

Abstract

We present a breakthrough of the strength-conductivity trade-off in cold wire drawn reduced graphene oxide (RGO)-aluminum (Al) composite. The composite was fabricated by a full glovebox powder metallurgy process, followed by hot rolling and wire drawing down to 0.5 mm wire diameter. Compared to the unreinforced Al fabricated by the same methodology, the incorporation of RGO in the 0.5 mm wire sample gave rise to approximately 20.7% improvement in mechanical strength, with only ~3.6% sacrifice in electrical conductivity. Furthermore, the 331.6 ± 6.8 MPa compressive strength and ~54.1%International Annealed Copper Standard (IACS) of the 0.5 mm wire RGO-Al composite exhibited a strength-conductivity combination comparable or even superior to conventional Al alloy conductors that go through complex thermal-mechanical treatments. Such a property synergy was interpreted by the ultra-fine Al grain structure and the elongated grain morphology rendered by the deformation processing steps, and an Orowan-typed strengthening mechanism owing to the homogenously dispersed natural amorphous alumina and RGO nanosheets in the composite.