Effect of Al₉₀Y₁₀ Amorphous Alloy Refiner on Microstructure and Mechanical Properties of A356 Aluminum Alloy

Al₉₀Y₁₀ amorphous alloy was added to A356 aluminum alloy melt as refiner to refine the alloy. The effect of refiner mass fraction (0, 0.2%, 0.4%, 0.6%, 0.8%, 1%) on the microstructure and mechanical properties of the aluminum alloy was studied. The results show that with the increase of Al₉₀Y₁₀ refiner content, the secondary dendrite spacing of the A356 aluminum alloy decreased first and then increased, the tensile strength, yield strength, elongation after fracture and hardness increased first and then decreased, and the tensile fracture form changed from quasi-cleavage fracture to quasi-cleavage and micropore aggregation mixed fracture. When the mass fraction of the refiner was 0.6%, the secondary dendrite spacing of the A356 aluminum alloy was 39.68% lower than that of the unrefined alloy, and the alloy showed the best mechanical properties. The yttrium aggregate phase formed after adding Al₉₀Y₁₀ refiner in moderation could reduce the precipitation of brittle phase, hinder the solute exchange between α-Al phase and eutectic silicon phase, thereby refining grains and improving mechanical properties.