Development of Novel Squeeze Cast High Tensile Strength Al–Si–Cu–Ni–Sr Alloys

The Taguchi method, as a design of experiment (DOE) technique, was used to develop squeeze cast high strength aluminum alloys containing elements of Si, Cu, Ni and Sr. The designed aluminum-based experimental alloys possess four factors: Si, Cu, Ni and Sr contents with three different levels of weight percentages (Si: 6, 9, 12%, Cu: 3, 5, 7%, Sr: 0.01, 0.02, 0.03% and Ni: 0.5, 1, 1.5%). Tensile properties including ultimate tensile strength, yield strength and elongation at failure were selected as three individual responses to evaluate the engineering performance of the designed alloys. An analysis of the mean of signal-to-noise (S/N) ratio implies that the tensile properties of the tested aluminum alloys are influenced significantly by the levels of the alloying elements in the Taguchi orthogonal array. The optimized major element content for the as-cast high strength aluminum alloy are 9% Si, 7% Cu, 0.03% Sr and 1.0% Ni. The percentage contribution of each factor is determined by the analysis of variance (ANOVA). The results indicate that the contents of Si and Ni are the most significant two factors influencing the tensile properties of the experimented alloys.