Browsing by Author "Saklakoǧlu N."
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Item Tribological behavior of PIII treated AISI 316 L austenitic stainless steel against UHMWPE counterface(2006) Saklakoǧlu N.; Saklakoǧlu I.E.; Short K.T.; Collins G.A.The aim of this work was to study the tribological benefits of PIII treated austenitic stainless steel by nitrogen ions and/or C ions in a ringer solution, which simulates the environment of the human body. This was achieved by hardness, wear and friction testing, and atomic force microscopy and XRD studies. The results showed that the samples, both treated and untreated, exhibited virtually no wear from contact with the ultra high molecular weight polyethylene (UHMWPE) pins, however, the pins themselves exhibited wear. The amount of wear of the pins was found to decrease with increasing PIII treatment temperature, but addition of C to the chamber caused some increase the amount of wear on the pins. Although C ions reduced to improve the hardness, friction characteristic was improved by formation of carbon-expanded austenite. © 2005 Elsevier B.V. All rights reserved.Item Tribological behaviour of plasma immersion ion implanted AISI 304 stainless steel against polymer and ceramic counterfaces(2007) Saklakoǧlu N.; Saklakoǧlu I.E.; Ceyhun V.; Aǧaçhan N.; Short K.T.; Collins G.A.Type 304 austenitic stainless steel samples were implanted with nitrogen using plasma immersion ion implantation (Pill) at different temperatures between 350 and 500°C. Treated and untreated samples have been studied by wear-friction testing, microhardness measurement and scanning electron microscopy (SEM).The experimental results indicated that the hardness and wear resistance is improved by increasing the penetration depth of nitrogen, whereas the friction coefficient is significantly increased by PIII. © 2007 Institute of Materials, Minerals and Mining.Item Characterization of surface mechanical properties of H13 steel implanted by plasma immersion ion implantation(2007) Saklakoǧlu N.AISI H13 steel samples were implanted with nitrogen using plasma immersion ion implantation (PIII) at 320 or 380 °C. In addition, PIII was used for simultaneous implantation of carbon and nitrogen into H13 steel at 380 °C. Treated and untreated samples were studied by wear-friction testing, microhardness measurement, atomic force microscopy and glancing angle X-ray diffraction (XRD) diagnosis. Experimental results indicated that the hardness and wear resistance were improved by increasing the PIII treatment temperature, whereas the presence of C ions does the opposite. It is explained by a nitride formation and a lattice expansion between 1.7 and 2.23%. © 2007 Elsevier B.V. All rights reserved.Item Effect of the surface nanocrystallization on tribological behavior of the Cu based bimetallic materials (CuPbSn)(Institute of Physics Publishing, 2019) Gencer G.M.; Yolcu C.; Kahraman F.; Saklakoǧlu N.In this study, ultrasonic impact treatment was used to improve the tribological behavior of copper-based bimetallic materials that are used in internal combustion engine bearings and bushes. Bimetallic materials were obtained by coating three different CuPbSn alloys by sintering on the material surfaces of carbon steel substrate. After the sintering process, bimetallic materials were treated by ultrasonic impact process. As a result of the metallographic examination, sintered layers have uniform structure along the cross-section of the bimetallic materials. In addition, it was determined that the porosity of sintered materials decreased after the ultrasonic impact treatment. Due to the grain refinement and work hardening, higher hardness was obtained in the fine-grained layer. The hardness of the ultrasonic impact treated samples always higher than the untreated material. Because of the high surface hardness, ultrasonic impact treated samples showed higher wear resistance. The highest wear resistance was detected in the samples with the highest Sn content. Because Sn and Cu combine to form Cu3Sn intermetallic phase in Cu-Pb alloys and Cu3Sn increases the strength of the Cu-Pb alloys. Thus, increasing the Sn content in the Cu-Pb alloy resulted in the wear resistance increase. Furthermore, the formation of the SnO2 intermetallic phase on the sample surface has a significant effect on the wear resistance increase by preventing adhesion. © 2019 IOP Publishing Ltd.Item Selective laser melting of Ti6Al4V alloy: Effects of process parameters at constant energy density on mechanical properties, residual stress, microstructure and relative density(Walter de Gruyter GmbH, 2023) Önder S.; Saklakoǧlu N.Selective laser melting is a production method that results in a large amount of residual stress due to high cooling rates and high thermal gradients. Although there are many studies examining the effects of process parameters on residual stress or mechanical properties in the literature, there are a few studies investigating the effects of changing laser power and scanning velocity (exposure time) at constant energy density on residual stress or mechanical properties and these studies have different results. This is a comprehensive study in this field that includes detailed comparisons with the results of similar studies in the literature. In this study, firstly specimens were produced at different process parameters and it was tried to find the process parameters that will obtain the highest relative density among the trials. Then at the constant energy density (85.0 J mm-3), which the maximum density has been obtained the effects of changing laser power and scanning velocity on residual stress, mechanical properties, microstructure and relative density were investigated. It was observed that at constant energy density, increasing or decreasing laser power and scanning velocity did not increase or decrease residual stress, tensile strength, % elongation and relative density monotonously. © 2022 Walter de Gruyter GmbH, Berlin/Boston.