High-strength magnesium composites reinforced with Sn–Ca and GNs–Y₂O₃ for automotive use

Reducing vehicle weight has become a key priority in the automotive industry, as it directly contributes to lowering fuel consumption and enhancing energy efficiency. Lightweight materials particularly magnesium alloys and their composites are playing an increasingly important role in boosting vehicle performance and minimizing energy usage. This focus is even more critical in electric vehicles (EVs), where reducing weight leads to greater energy savings, extended driving range, and improved overall efficiency. In this study, a new fabrication approach was developed to produce high-strength magnesium (Mg) composites. The method combines cold pressing with hot compaction, where samples were cold-pressed and then compacted at 450°C under a pressure of 800 MPa for 25 min. To improve the mechanical and tribological performance of the composites, magnesium was reinforced with a binary Sn–Ca system and a hybrid mixture of graphene nanosheets (GNs) and yttria (Y 2 O 3 ). The results demonstrated clear enhancements in the properties of the fabricated composites. Alloying magnesium with 15 wt% tin and 5 wt% calcium increased the hardness from 47.7 HV to 68.5 HV and raised the yield strength to 193 MPa. Additionally, the Sn–Ca reinforced composite exhibited the lowest wear rate (0.0122 g/min) and showed a significant reduction in the coefficient of friction compared to pure magnesium. The incorporation of graphene nanosheets and yttria further improved the density and microstructural refinement of the composites, leading to better overall performance.