The investigation of microstructure and mechanical properties of Pb-Sn-Cu alloy bearing meterials

ABSTRACT Master Thesis THE INVESTIGATION OF MICROSTRUCTURE AND MECHANICAL PROPERTIES OF Pb-Sn-Cu ALLOY BEARING MATERIALS Tanju TEKER Fırat University Instate of Natural Sciences Department of Metallurgical Education 2004, Page: 41 In this study, the effect of % 5-6 Co and %7-8Cr addition on the journal bearing alloy including % 73,4 Pb- % 23,4 Sn- % 3,2 Cu were investigated. The study have a very important role from its microstructure and mechanical properties growing Pb bronze that is excellent alloy for high speed worked slippery bearing. With this aim, Pb-Sn-Cu alloy have been cast by injection process. The solidification structures were determined by metallographical techniques and mechanical teste. The changes on micro structure and mechanical properties of alloy were determined by optic microscope (OM), Scanning Electron Microscopy (SEM), Electron Diffraction Shot (EDS), X-Ray Diffraction (XRD) and Differential Thermal Analyses (DTA), tensile test and micro hardness tests. In the first chapter of mis study, the Pb-Sn-Cu alloys and their importance are introduced. In the second chapter, materials and method are given. In this chapter, also the technical characteristics of the elements of slippery bearing alloys. In the third chapter experimental studies are presented. In the fourth chapter, the results of the experiments, the conclusions and recommendation are given. As a result, the ductility of Pb- % 3-3,5 Cu- % 23-24 Sn alloy had been decreased by Co and Cr addition. However, Co caused an increase of the yield strength and Cr decreased both the yield strength and ductility considerably. Although Co and Cr contents raises the melting point of alloys, its phase transformation decreases. Keywords: Pb-Sn-Cu alloys, injection casting, mechanical properties, micro structure, SEM, EDS, XRD, DTA. vn