Fabrication and Mechanical Characterization of TiB2-Graphene Reinforced AA 6061 Composite by Friction Stirr Processing

In this research, friction stir processing was used to produce mono and hybrid surface composite layers of aluminum matrix containing TiB2 and graphene particles. Microstructural evaluation of the samples was performed by optical microscopy and field emission scanning electron microscopy of the composite samples cross-sections. The mechanical properties of the samples were investigated using microhardness and tension tests. Among the samples reinforced with TiB2 and graphene, the samples with 20wt% TiB2 and 1wt% graphene exhibited the highest hardness and strength compared to other samples. Aso, the highest mechanical properties are observed in the sample reinforced with hybrid powders include 20wt% TiB2 and 1wt% graphene. The yield and ultimate strength of the sample increased from 75 and 160MPa (corresponding to the initial 6061 AA) to 191 and 271MPa, respectively. Also, the average hardness of this sample in the stir zone is equal to VHN101 which was significantly higher than the initial alloy (VHN62) and the non-powdered friction-stir sample (VHN71).