Ph.D. Tezi Görüntüleme | |||||||||||||||||||||
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| Summary: A series of zinc-aluminum, zinc-aluminum-copper and zinc-aluminum-copper-silicon alloys were produced by permanent mould casting. The microstructure and mechanical properties of the alloys were examined in the as cast and heat treated conditions and the effect of chemical composition and heat treatment on the properties of these alloys were determined. The friction and wear properties of the zinc-aluminum based alloys were examined under static loading using a pin-on-disc test machine, and the tribological properties of the bearings produced from these alloys were investigated under both static and dynamic loading conditions using a bearing test rig. The zinc-aluminum based alloys and bearings produced from these alloys exhibited higher wear resistance than the CuSn12 bronze and the bearing produced from this bronze. The lowest wear rate or highest wear resistance was obtained with the bearings produced from ZnA140Cu2Si1 alloy which had the lowest coefficient of friction. The bearings produced from the zinc-aluminum based casting alloys showed higher wear resistance than those produced from the heat treated alloys under static loading condition. However, the bearings produced from the heat treated alloys exhibited higher wear resistance under dynamic loading than those produced from the alloys in the as cast condition. The wear resistance of the bearings produced from the cast alloys under static loading were found to be higher than that obtained under dynamic loading. It was also found that the wear resistance of the bearings produced from the monotectoid based alloys increased with increasing copper content up to 2% Cu, above which it decreased with increasing copper content. The wear results obtained from the alloys using the pin-on-disc machine were found to be in a good agreement with the wear results obtained from the bearings produced from these alloys using the bearing test rig under static loading.As a result of this study, the bearings produced from the zinc-aluminum based casting and heat treated alloys showed much higher wear resistance than the bronze bearings under both static and dynamic loading. Among all the bearings tested, the best wear performance was obtained with the bearings produced from ZnA140Cu2Si1 alloy. Keywords : Zinc-Aluminum Based Alloys, Wear Test Rigs, Static and Dynamic Loadings, Sliding Bearings, Friction and Wear
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