High strength and conductivity copper matrix composites reinforced by in-situ graphene through severe plastic deformation processes

• Published in: Journal of alloys and compounds 2021-01, Vol.851, p.156703, Article 156703
• Main Authors: Li, Tiejun, Wang, Yaoqi, Yang, Ming, Hou, Hongliang, Wu, Sujun
• Format: Article
• Language: English
• Subjects: Cold drawing; Cold extrusion; Conductivity; Copper; Copper matrix composites; Dislocation pinning; Dispersion; Electronic properties; Grain boundaries; Grain structure; Graphene; High temperature; Hot extrusion; In-situ graphene; Interfacial bonding; Mechanical properties; Metal matrix composites; Particulate composites; Plastic deformation; Polymer matrix composites; Severe plastic deformation; Tensile strength
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2020.156703

The dispersion of graphene in copper matrix and their interfacial bonding quality decisively determine the comprehensive performance of graphene/copper composites. To explore the possibility of dispersing the well-bonded graphene evenly in the copper matrix, we tested various processing methods and obtained a unique copper-based composite reinforced by in-situ graphene, achieved by two severe plastic deformation processes of hot extrusion and cold drawing. The experimental results revealed that the in-situ graphene was in the form of shreds and uniformly dispersed in the copper matrix. The abnormal coarsening of copper grains occurred during the graphene depositing process due to high temperature, but the grains were then refined during the following severe plastic deformation process. Graphene can play a role of pinning dislocations and hindering grain boundary slip, thereby improving the strength of the composite. Meanwhile, the network structure of graphene in the copper matrix provides a fast path for electron transmission which can make up for the negative effect of the fine of copper grain structure on the conductivity. The tensile strength and conductivity of the composite reach to 595 MPa and 5.46 × 107 S/m, representing an increase of 23.4% in tensile strength, and similar conductivity (98%) of the original copper matrix. [Display omitted] •A novel method for preparing high strength and conductivity graphene/copper composite wire is provided.•The graphene is uniformly dispersed inside the copper matrix during the large deformation process for its poorer plasticity.•The copper grains grew abnormally under high temperature, and were refined during the severe plastic deformation process.•The network structure of graphene can make up for the decrease of conductivity caused by refinement of copper grains.