Özet:

In recent years, zinc-aluminium (ZA) alloys have found increasing uses in several applications because these alloys exhibit a good combination of mechanical, physical and tribological properties along with low cost of fabrication. In order to further enhance some of the properties of non-ferrous alloys, many attempts have been made to produce MMCs with Al alloys, Mg alloys, Cu alloys and Ti alloys as the matrix materials.  Literature on aluminum alloy composites suggests the effective use of graphite as a potent reinforcement. The absence of data on ZA alloys with graphite reinforcement was the stimulus for pursuing this systematic work. In this study, the results of the experimental investigation with varying graphite reinforcements on the microstructure and wear loss of the popular gravity die cast ZA base alloys (viz., ZA8, ZA12 and ZA27) is reported. The wear tests were conducted using pin-on-disc apparatus to assess the wear loss at three different loads (20N, 29N and 39N) and at constant speed of 200rpm. The results showed that the wear loss decreases with the addition of graphite from 2wt.% to 6wt.% in the ZA8, ZA12 and ZA27 base alloys and it increases with increasing loads. The studies indicate that the wear loss of ZA8 and ZA12 were higher than that of ZA27 based composites. Design of experiments (DOE) denotes the methodology of application of statistical techniques in experimentation. This has been attempted in this work, for the first time for the ZA alloy based composites.  Proceeding further, multiple regression models have been worked out for the UTS, YS, %E, and BHN. Confirmation test results are in good agreement with the values predicted.

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