Reduced graphene oxide and alumina synergistically enhance the mechanical and wear properties of WC-8Co cemented carbide

Graphene oxide (GO) was used to adsorb submicron alumina (Al 2 O 3 ) as a composite reinforcing phase, and after sintering, the reduced GO and Al 2 O 3 synergistically enhanced the performance of WC-8Co cemented carbide . It was worth noting that the enhanced phase existed at the grain boundary in the form of RGO/Al 2 O 3 adsorption structure or partial alumina alone, which wraped the WC grain and hindered its growth. The results showed that the strengthening mechanism of the alloy was grain refinement, dispersion, solid solution , etc., and it was calculated that grain refinement was the main mechanism of alloy hardness enhancement. When 0.1 wt% RGO/Al 2 O 3 was added, the average grain size of the alloy was reduced to 0.65 μm, and the density reached 99.46%. Additionally, the mechanical properties of the alloy were optimized in this study. For WC-8Co-0.1RGO/Al 2 O 3 alloy, the hardness was increased by 18.05%, and the fracture toughness was increased by 27.24% relative to the control sample. In addition, the RGO/Al 2 O 3 significantly enhanced the thermal conductivity of the alloy, promoted densification, and reduced the degree of oxidative wear caused by friction. RGO/Al 2 O 3 in the alloy protected the matrix and improved its frictional resistance by adhering to the surfaces of the wear tracks and combining with the wear debris to form a stable friction layer.