Improvement of Microstructure, Mechanical Properties and Corrosion Resistance of Cast Al-12Si Alloy by Friction Stir Processing

摘要

Friction stir processing (FSP) was applied to casting and non heat-treated strengthening of Al-12Si aluminum alloy in order to enhance the mechanical properties by improving the microstructure. Moreover, the corrosion resistance of FSPed Al-12Si alloy is also examined. The results indicate that intense plastic deformation during FSP effectively results in the grain refinement of Al-12Si alloy, uniform distribution of Si particles and elimination of cast porosities, and the microstructures of Al-12Si alloy are significantly improved. The microhardness, tensile strength and elongation are increased to 57.15 HV, 159.39 MPa and 9.87% after FSP, respectively, The surface fracture of the FSPed tensile specimen exhibits a typical ductile dimple-fracture. Grain-boundary strengthening and dispersion strengthening of Si particles play important roles in enhancing the mechanical properties. Meanwhile, compared with cast alloy, FSPed Al-12Si alloy has more excellent corrosion resistance.