Few-layered graphene/Al-Cu alloy matrix composites: Mechanical, tribological and corrosion properties

Abstract

Nano-sized graphene incorporated Al-5.5 wt% Cu alloy matrix composites were produced via powder metallurgy. Nano-sized graphene powders obtained via the arc-discharge method were incorporated into Al and Cu powders in varying amounts (0-5 wt%) by applying a high-energy ball milling (HEBM) process for different durations. The consolidated composites were prepared by the succeeding uni-axial pre-compaction and pressureless sintering stages. The as-blended and mechanically alloyed (MAed) powders and bulk composites were comparatively characterized in terms of their physical, thermal, microstructural, tribological, mechanical, and corrosion properties depending on the graphene amount and the duration of mechanical alloying (MA). After 4 h of MA, the starting as-blended powders presented as coarse and discrete particles gained a refined and homogenized microstructure with more equiaxed dimensions. Bulk FLG/Al-5.5Cu (FLG in amounts of 0, 0.5, 1, 2, and 5 wt%) composites are ever-increasing hardness values with rising graphene as 109, 101, 128, 238, and 263 HV, respectively. The compressive strength improved gradually to 495 MPa using graphene up to 1 wt%, though contrary to the high hardness values, a drastic decline was observed by 5 wt% graphene incorporation. Besides, the wear resistance of composites outperformed that of the Al-5.5Cu matrix by incorporating this amount of reinforcement together without a deterioration in the corrosion resistance.