WC-modified graphene for melt-processed copper composites with high strength and conductivity

Melting process is the most efficient and economical method for industrial-scale copper production. However, graphene/copper (Gr/Cu) composites are difficult to fabricate by this method due to the extremely poor wettability between graphene and molten copper, which hinders uniform dispersion. To address this challenge, tungsten carbide (WC) modified physically exfoliated graphene (WG_P), synthesized via carbothermal reduction, was introduced into molten copper. By adjusting the WC content, the wettability of WG_P with molten copper was significantly improved, reducing the contact angle from 140° to 29.2° and enabling uniform dispersion in the matrix. The resulting composite with an initial input of 5 wt% WG_P (5WG_P/Cu) achieved an actual mass fraction of 2.34 wt%, exhibiting a tensile strength of 506 MPa in the cold-rolled state, retaining 310 MPa after annealing at 500 °C for 10 min. After annealing, 2WG_P/Cu exhibited an electrical conductivity (EC) of 101.6% IACS at 20 °C, and at 180 °C its EC remained 2.7% higher than that of pure Cu measured at the same temperature. van der Waals interaction analysis based on Lifshitz theory revealed that interfacial WC plays a decisive role in enabling spontaneous capture during solidification. Molecular dynamics (MD) simulations demonstrate that the WG_P-Cu interface exhibits a more pronounced load transfer effect compared with the G_P-Cu interface. This work overcomes a critical bottleneck in the molten-state processing of Gr/Cu composites and provides a scalable, industrially viable strategy for high-performance composite production.