Al-Mg2Si composite materials are widely employed in aerospace, electronic research, automotive industry and among various other fields due to its superior mechanical propertys. The microstructure of Al-10Mg2Si composite materials with varying Y contents was analyzed using X-ray diffraction (XRD), 3CCD real-color confocal microscope (3CCD), field emission scanning electron microscope (SEM), and transmission electron microscope (TEM). Concurrently, the mechanical properties were evaluated through hardness testing and tensile testing using a microhardness tester and a universal testing machine, respectively. The experimental findings indicated that the inclusion of Y in the Al-Mg2Si alloy resulted in the presence of three distinct phases: α-Al, Mg2Si, and Al3Y. The primary growth of the Al-10Mg2Si alloy with Y addition resulted in a refinement of the α-Al structure and the modification of the eutectic Mg2Si structure. With increasing Y content, the strength and elongation of the Al-10Mg2Si alloy initially showed an upward trend followed by a decline. The maximum tensile strength and total elongation of the Al-10Mg2Si alloy with Y addition reached 320 MPa and 6.2%, respectively. The incorporation of Y effectively refines the primary α-Al phases into a circle-like and creating Al3Y phases can be used as a heterogeneous nucleation substrates. After modification, the fracture surface of the alloy transformed from a large area of brittle fracture with full cleavage planes and tearing edges to a ductile fracture filled with tough dimples. Thus, this study offers a simple optimized method to enhance the modification efficiency of Y in hypoeutectic Al- Mg2Si composites.
