Effect of copper content on thermal and mechanical properties of eutectoid zn-al alloy

Zn-Al alloys have become one of the major engineering alloys among commercially available alloys. This study was conducted on eutectoid composition of Zn-Al alloy with an observation of the effect of copper addition. For this purpose, one eutectoid (Zn-22wt%Al) and three other alloys, adding 1wt%, 3wt% and 5wt% copper with this eutectoid composition, were molded in permanent metal mould. Microscopic studies exhibited varied grains which confirmed the formation of different phases. Moreover, the formation of different phases in micro study was supported by XRD analysis. Hardness of the samples were tested on Rockwell B scale and it was observed that the hardness of these alloys was substantially increased with the addition of copper. With increasing amount of copper, phase changing temperature of the alloys reveals a growing trend, which was observed by DTA analysis. From this study it was concluded that addition of copper can significantly add to the mechanical properties of Zn-Al alloys.