Al–Si–Cu–Mg Matrix Composites with Graphene: PM-Based Production, Microstructural, and Mechanical Properties

Few-layered graphene (FLG)-reinforced Al-Si(10 wt%)-Cu(2 wt%)-Mg(1 wt%) matrix composites are prepared by the high-energy mechanical alloying (MA) method, which is a branch of powder metallurgy. Al-10Si-2Cu-1Mg matrix is reinforced with varying amounts of FLG (0, 0.5, 1, 2, and 5 wt%) via MA for different durations (0, 2, 4, and 8 h), and consolidation is conducted by pressureless sintering. Microstructural, mechanical, and tribological characterizations are applied to nonmechanically alloyed (non-MAed) and mechanically alloyed (MAed) powder and bulk composites comparatively. The bulk composites produced via the MA-containing processing route illustrate more homogeneous phase distributions and higher densification rates. The FLG/AlSiCuMg composites exhibit enhanced materials properties compared to their unreinforced counterparts. The addition of 1 and 2 wt% FLG to the Al-10Si-2Cu-1Mg alloy, respectively, improved the mechanical properties in terms of microhardness (155 and 162 HV), compression strength (441 and 412 MPa), and wear rate (11.5 × 10⁻⁴ and 9.2 × 10⁻⁴ mm³ N⁻¹ m). Therefore, the experimental results show that graphene ensures a reinforcing effect on the Al matrix, at least provided by some of the ceramic particles.