<p>Although graphene is regarded as a promising reinforcement for aluminum matrix composites (AMCs), its influence on the corrosion behavior in the low concentration range (≤ 0.5&#xa0;wt.%) remains unclear. In this study, aluminum matrix composites with varying graphene contents (0–0.5&#xa0;wt.%) were fabricated via vacuum sintering, and the effects of graphene content on the microstructure and corrosion properties were systematically investigated. Results show that the composite with 0.1&#xa0;wt.% graphene exhibits the best corrosion resistance, with a corrosion current density of 5.5230 × 10⁻⁷A·cm⁻² and a corrosion rate of 0.0187&#xa0;mm/a. Microstructural characterization reveals that graphene is uniformly distributed along the grain boundaries without obvious agglomeration at this concentration. In contrast, when the graphene content increases to 0.5&#xa0;wt.%, agglomeration occurs at the grain boundaries. This leads to reduced interfacial bonding and disruption of the surface protective film, resulting in an increase in the corrosion current density to 3.91 × 10⁻⁶ A·cm⁻².</p> Graphical Abstract <p>Graphene/Al-matrix composites for drilling rods were fabricated through a synergistic process combining ultrasonic dispersion, mechanical stirring and vacuum sintering. Systematic study reveals that 0.1 wt.% graphene addition yields uniform grain boundary distribution, leading to the optimal microstructure and the most significant enhancement in corrosion resistance. </p>