Copper coated graphene reinforced aluminum composites with enhanced mechanical strength and conductivity

Abstract

Traditional methods to enhancing mechanical strength of metallic materials would result in the inverse effect on the conductivity and how to prevent this inversed relationship between strength and conductivity has been a long-known problem, especially for electrically conductive materials. Here we report a strategy that utilize copper coated graphene as reinforcement, concurrently enhancing both the mechanical strength and electrical conductivity of aluminum matrix. Copper coated graphene reinforced composites were fabricated through a sequence of procedures involving chemical deposition, ball milling, and vacuum hot-pressing sintering processes. Copper coating on graphene not only avoids graphene from agglomeration but also prevents the development of degraded Al4C3 phase as well as increasing the interface bonding and the electrical contact between reinforcements and the matrix. The composite possesses an ultimate tensile strength of 242 MPa and a conductivity of 34.5 MS/m, respectively, with introducing 0.5 vol% graphene, which is around 102% and 8.15% higher than the corresponding values for pure aluminum manufactured under the same circumstances. Compared to other routine methods, this approach effectively tackles the enduring challenge of reconciling the trade-off between strength and electrical conductivity in metallic materials.