Evolution of Microstructure and Wear Properties of Heat Treated Copper-graphene Composite Fabricated by Accumulative Roll Bonding

This research aims to investigate and develop the wear properties of the copper-graphene composite, which is utilized in electrical contacts, the railway, and electronics industries. In this research effects of annealing temperature on wear resistance and microstructure in copper-graphene composite fabricated by the accumulative roll bonding (ARB) method was studied. The samples were annealed at 200 (S200), 300 (S300), and 500 °C (S500) for 1.5 hours. The wear test was performed using a steel (Chromium steel) pin and the pin-on-disk method with a normal force of 10 N. In addition, wear tracks were analyzed using scanning electron microscopy and energy-dispersive spectroscopy. An adhesive wear mechanism was observed in all samples. With the increase of annealing temperature, the mechanism of oxidation and adhesive wear changed to scratch, groove, and dullness along with severe plastic deformation. Regarding the wear properties, the results showed that the wear rate increases with the increase in the annealing temperature. This way, the wear rate reached from 1.16 × 10-6 g/m in the R sample to 3.15 × 10-6, 3.93 × 10-6, and 6.34 × 10-6 g/m in the S200, S300, and S500 samples. By examining the microstructure of the annealed samples and comparing them with R (as-fabricated sample), It was observed that with increasing annealing temperature, the grain size in S200, S300, and S500 samples increased from 6.63 to 9.67, 14.3 and 16.79 µm, respectively. The microhardness of the S500 sample decreased by 45.11% (From 121.12 to 58.47 Hv) compared to R, which was ascribed to grain growth.