Graphene-Reinforced (Cu–WC–Ni) Hybrid Nanocomposites: Properties and Microstructure
摘要
In this study, Cu–20%WC–5%Ni hybrid nanocomposites reinforced with varying graphene nanoplatelet (GNP) contents (1.2–1.8 wt.%) were fabricated via powder metallurgy. The process involved pre-mixing WC, Ni, and GNP powders for 6h to ensure uniform dispersion, followed by electroless copper coating. The composites were then compacted at 800 MPa and sintered at 1050 °C for 120 min under a hydrogen atmosphere. The effect of GNP content on microstructure, hardness, compressive strength, and electrical conductivity was systematically investigated. Microstructural analysis revealed excellent dispersion of WC and Ni in all samples due to the electroless copper coating, with minor GNP agglomeration appearing from 1.4 wt.% GNPs. The intermetallic phase Ni2W4C was detected in the 1.2 wt.% GNP sample but disappeared at higher graphene contents. Vickers hardness increased gradually from 274 HV (1.2 wt.% GNPs) to 316.5 HV (1.8 wt.% GNPs) under a 10 kgf load for 15s. In contrast, compressive yield strength decreased with GNP addition, attributed to sliding between agglomerated graphene layers, while fracture behavior transitioned from brittle to ductile, with the 1.8 wt.% GNPs sample showing pronounced plasticity. Electrical conductivity improved from 3.97 × 107 S/m (1.2 wt.% GNPs) to 5.95 × 107 S/m (1.4 wt.% GNPs, 49% enhancement), but higher GNP contents reduced conductivity due to electron scattering by graphen clusters.