Tensile properties of three-dimensionally interconnected graphene-networked Cu composite and changes in its microstructure in relation to heat treatment temperature

Abstract

An investigation of microstructure changes in a new, in situ-fabricated, three-dimensionally interconnected graphene-networked Cu composite was performed in relation to the heat treatment temperature in H2 and in air. Heat-treated in H2 revealed that recrystallization commenced at ~ 300 ℃ and the crystal grew afterward. However, the crystal growth was constrained within the initial Cu grains and inhibited due to Cu grains being wrapped by the stable graphene, even at 1000 ℃. This resulted in similar or narrower grain-size distribution. Meanwhile heat treatment in air resulted in the oxidation of carbon, instability of graphene, and crystal growth over the grain boundaries, which resulted in a wider grain-size distribution. Increases in tensile and plastic deformation (30% and 144%, respectively) were observed due to the grain size refinement and the strong interfacial bonds between graphene and the Cu matrix. The result was greater load bearing and toleration of a substantial load during plastic deformation.