INFLUENCE OF ZINC AND MAGNESIUM ADDITION ON THE FLUIDITY OF Al-Zn-Mg ALLOY

Abstract

The goal of this research was to investigate the influence of zinc and magnesium on the fluidity of Al-Zn-Mg alloy. The fluidity test was carried out using a serpentine-shape sand mould. The length of the serpentine-shape pattern was 180 cm. The experiment was designed by varying the compositions of zinc from 1 to 5 wt%, and magnesium from 0.5 wt% to 2.5 wt%. Variation in compositions of the two elements was done separately, and later a combined variation in compositions of zinc and magnesium was investigated. The superheat temperature was placed at 70ºC above the liquidus temperature. From the results obtained, it was observed that there was general increase in fluidity when the percentage weight composition of magnesium was increased. Alloy with 2.3 wt% Mg was found to have the highest fluidity, followed by alloy with 2.85 wt % Mg. When the percentage weight compositions of zinc were increased, there was a general decrease in fluidity of the Al-Zn-Mg alloy, in which alloy with 5.14 wt % zinc recorded the lowest fluidity of 57.1 cm as compared to the as-cast alloy. Also for the combined variation in compositions of zinc and magnesium, it was discovered that there was decrease in the flow length of the alloy, where alloy with 5.14 wt% Zn and 2.85 wt% Mg combined has flow length of 59.8 cm. But the reduction in fluidity length when the composition of zinc was varied was more drastic as compared to that of the combined alloying elements.