Powder metallurgical fabrication of graphene reinforced near-eutectic Al-Si matrix composites: Microstructural, mechanical and electrochemical characterization

Al-10 wt% Si matrix composites reinforced with a few-layered graphene (FLG) were fabricated via a powder metallurgical route. FLG in varying amounts (0.25, 0.5, 1, 2, and 5 wt%) was incorporated into the Al10Si matrix via mechanical alloying (MA) for different durations in a high-energy ball mill. The mechanically alloyed (MAed) powders were consolidated by uniaxial pressing and pressureless sintering processes. The as-blended (non-MAed) and MAed powders and bulk composites were investigated comparatively in terms of microstructural, thermal, mechanical, tribological and corrosion properties. The MAed powders demonstrated refined and semi-equiaxed particle morphology with reduced crystallite size values. Additionally, the FLG/Al10Si composites exhibited advanced microstructural and mechanical properties by the contribution of MA and reinforcing particles compared to those of the as-blended and unreinforced matrix. The highest hardness and lowest wear rate values were obtained for the 4 h-MAed Al10Si-2FLG (138 HV and 6.485x10-4 mm(3)/N.m) and Al10Si-5FLG (178 HV and 7.456x10-4 mm(3)/N.m) composites. Moreover, the compressive strength of the Al-10Si matrix improved approximately by 50 and 20% via 0.5 and 2 wt% FLG addition, respectively. Also, lower corrosion resistance properties were observed for the FLG reinforced composites compared to the Al10Si matrix. (c) 2021 Karabuk University. Publishing services by Elsevier B.V.

Automated summary

The FLG/Al10Si composites showed improved microstructural and mechanical properties after mechanical alloying treatment, with increased hardness and reduced wear rate, but lower corrosion resistance.