Abstract
The low level of wear and damage resistance makes it impossible to further improve aluminum alloy 7075 that is used in making light constructions. This research focuses on micro-nano hybrid reinforcements on microstructure, mechanical, and tribological properties of Al 7075-based hybrid metal matrix composites reinforced with silicon carbide and graphene nanoplatelets. The hybrid reinforcement consists of 5 wt.% silicon carbide and 0.25, 0.50, and 0.75 wt.% graphene nanoplatelets under liquid metallurgy and T6 treatment.
Under low volume-fraction conditions, the composite microstructure contains a uniform distribution of SiC particles and graphene nanoparticles. Significant grain refinement occurs. With increasing GNP volume, nanoparticle agglomeration improved hardness, tensile strength, and wear resistance while degrading other properties. Mechanical properties of the GNPs were enhanced due to the load transfer, Orowan, thermal mismatch, and grain refinement effects.

Key words
Al-7075, hybrid composite, SiC, graphene nanoplatelets, relationship microstructure-property, Orowan strengthening, wear behaviour

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