Modification effect of Sr on the microstructures and mechanical properties of Al-10.5Si-2.0Cu recycled alloy for die casting

The effect of Sr addition on the microstructure and mechanical properties of Al-10.5Si-2.0Cu (in wt%) recycled die-casting alloy was studied. With increasing Sr content, the morphology of the eutectic Si evolved from coarse acicular -> lamellar -> fine fibrous shapes. Sr addition significantly improved the mechanical properties, with the tensile strength being increased from 209 to 237 MPa and the elongation from 2.0 to 4.1%. This improvement was associated with the morphological evolution of the eutectic Si and was qualitatively evaluated by using a quality index. (C) 2011 Elsevier B.V. All rights reserved.