Optimizing the tensile properties of Al–11Si–0.3Mg alloys: Role of Cu addition

Abstract

In the present work, the role of Cu addition on the tensile properties of both as-cast and solution-treated Al–11Si–0.3Mg alloys was systematically investigated. For as-cast alloy, a fine and uniform microstructure can be obtained by employing efficient refinement and modification with the combinative addition of B, La and Sr. The addition of Cu causes slight coarsening of α-Al dendrite, but has insignificant effect on the size and morphology of eutectic Si particles, resulting in a promotion of strength coupled with unremarkable reduction of elongation. The strengthening effects of Cu addition mainly depends on the weight ratio of Cu/Mg in the experimental alloy, of which the quality value of Q calculated shows that the optimized tensile properties of Cu-dropped Al–11Si–0.3Mg can be achieved with the weight ratio of Cu/Mg of 5:1, referring to 383MPa and 430MPa in as-cast condition and solution-treated condition, respectively.