Browsing by Author "Korkmaz, Şeyma"

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Citation - WoS: 2
Citation - Scopus: 2
Effect of Shot-Peening Process and Nanoparticle-Added Lubricant on the Tribological Performance of Aluminium-Based Sliding Bearing Material
(Wiley, 2024) Korkmaz, Şeyma; Çetin, M. Hüseyin; Simsir, Hamza; Ünal, Okan; Temel, Farabi
In this study, it is aimed to increase the wear and fatigue performance of aluminium-based sliding bearing material by using silver nanoparticles (AgNPs) added lubricant and shot-peening process. The main purpose is to minimise the wear of the bearing material by penetrating AgNPs added lubricants into the rough surfaces formed by shot peening. Almen intensity, coverage and shot size parameters in the shot-peening process were analysed in terms of hardness, surface roughness and fatigue strength. The shot-peened aluminium bronze was subjected to wear experiments under dry, pure water and AgNPs added lubricant conditions. The wear test results were analysed in terms of friction coefficient, wear volume and surface roughness parameters, and the interaction of lubricant and shot-peening parameters was evaluated. According to the results of the shot-peening experiments, the Almen intensity was the most effective parameter in terms of hardness and surface roughness (91.62%). It was concluded that the hardness value was 8% higher at high Almen (12-14A) intensity compared with low Almen intensities, and the shot-peening process could increase the fatigue strength by similar to 21 times. According to the wear tests, the most effective parameters were 4-6 Almen intensity and AgNP-added lubricant.
Citation - WoS: 6
Citation - Scopus: 5
Investigation of Interaction of Extreme Pressure Additive, Load and Sliding Speed Parameters With Silver Nano-Particles in Wear Environment
(IOP Publishing Ltd, 2021) Ahmaida, Yousef Alamin A.; Korkmaz, Şeyma; Kılınçarslan, Sena Kabave; Şirvan, Onur Can; Çetin, Muhammet Hüseyin
This study aims to minimize the wear of brass-based sliding bearing materials by using extreme-pressure and nano-silver added lubricants. The nano-fluids used in the experiments were characterized by the Zeta test, size measurement, absorbance graphs, wettability analyses and TEM imaging. The effect of extreme-pressure (5%, 10% and 15%) and nano-silver (1%, 5% and 9%) concentration ratios and the interaction of lubricants with load and speed parameters were analyzed with ball-on-plate wear experiments. The results were analyzed by evaluating the friction coefficient and wear volume values, as well as SEM and 3D topography images. It has been found that 5% extreme pressure lubricant reduces friction coefficient by 32.82% and volume loss by 89.51% compared to base lubricant. According to the results, the lowest friction coefficient (0.0276), volume loss (0.042 mm(3)) values and the best surface images were obtained at 1% concentration. Furthermore, the tribological performance decreased as the concentration of extreme-pressure and nano-silver increased, and optimum extreme-pressure and nano-silver concentrations were obtained as 5% and 1%, respectively. Using additives, different load (10N, 20N and 30N) and speed (10 rpm, 25 rpm, 40 rpm) parameters, Taguchi's L9 fractional factorial experimental design was created for interaction analyses. With the Taguchi analysis of the design, 5% extreme pressure added lubricant, 10N load and 40 rpm speed parameter combination was determined as the optimum test condition and base lubricant, 30N load and 25 rpm speed parameters were determined as the worst test condition. According to the variance analyses results, it was determined that the lubricant condition was the most effective parameter on the coefficient of friction (67.79%), volume loss (51.07%) and surface roughness (45.43%).
Investigation of Tensile Strength and Hardness Behaviour of Hardox500 – St52 Specimen Joined by Gmaw Method
(Konya Technical University, 2020) Korkmaz, Şeyma; Çetin, Muhammet Hüseyin; Adar, Muhammed; Orak, Abdulkadir
In mechanical construction, meeting different industrial requirements such as high strength,wear and corrosion resistance can be achieved by using different materials together. Especially the usageof metallic materials together is important for sustainability. The use of different metallic materialstogether depends on the joining ability of the materials andexperimental studies are needed for theanalysis of joining ability.In this study, the weldability of Hardox500 and St52 (S355) steel by GMAW (GasMetal Arc Welding) method was investigated using different current and voltage parameters. Weldabilityof two different steel alloys were examined by tensile test, micro hardness measurement, SEM andmicrostructure imaging techniques. Tensile tests were applied to the welded samples and the criticalpoints and deformation characteristics of the samples were evaluated according to the determined inputparameters. Micro hardness values of the samples were determined by Vickers (HV) hardnessmeasurement method. According to the results, it was determined that the welding capability ofHardox500 and St52 material was low at low current and voltage values and that the hardness distribution occurred irregularly. It was determined that the tensile curves at high current and high voltage values exhibited more stable behaviour and a homogeneous hardness distribution occurred.