Yazar "Karadag, H. B." seçeneğine göre listele

Listeleniyor 1 - 2 / 2
  • Küçük Resim Yok
    Öğe
    Effect of Sodium Hypochlorite and Hypochlorous Acid Solutions on the Cyclic Fatigue Resistance of Waveonegold, K3XF and Hyflex-EDM: A Study of Metallurgical Properties
    (Springer, 2023) Bozkurt, D. A.; Akman, M.; Karadag, H. B.; Ovalioglu, Z.; Keles, O. Kucuk
    The presented work was focused on investigating the effects of sodium-hypochlorite (NaOCl) and hypochlorous-acid (HOCl) solutions on the dynamic cyclic fatigue resistance of WaveOneGold (WOG), K3XF and Hyflex-EDM (HEDM) nickel-titanium (Ni-Ti) instruments. A total of 141 Ni-Ti instruments were included in the study, 45 of each file for cyclic fatigue testing and two for metallurgical analysis. The NiTi instruments were rotated in an artificial canal that was immersed in three different solutions [2.5% NaOCl, HOCl or distilled water (DW)] at body temperature until fracture occurred and the time to fracture (TtF) in seconds was recorded. Fractured and unused files were analysed by scanning-electron-microscopy (SEM) with energy-dispersive X-ray spectrometry (EDS), X-ray diffraction (XRD), and a microhardness tester. The mean data were analyzed statistically using Kruskal-Wallis, and post hoc Mann-Whitney-U test. The TtF of the HEDM was statistically significantly higher than that of WOG and K3XF for all solutions. It was found that 2.5% NaOCl and HOCl solutions reduced the TtF of the WOG, but had no significant effect on the K3XF and HEDM. By EDS analysis, it was determined that titanium-oxide compounds were formed on the file surfaces at most in 2.5% NaOCl solution. The highest hardness value was K3XF, and the lowest hardness value belonged to the HEDM instrument. The HOCl solution can be used as an alternative irrigation solution as it is less corrosive to the instruments compared to than NaOCl solution.
  • Küçük Resim Yok
    Öğe
    The mechanical properties of composite materials recycled from waste metallic chips under different pressures
    (Springer, 2019) Aslan, A.; Salur, E.; Gunes, A.; Sahin, O. S.; Karadag, H. B.; Akdemir, A.
    The purpose of this study is to produce composite materials by utilizing the waste metallic chips. In this context, the metal matrix composite materials (MMCs) were produced at different production pressures and the effects of the different pressures on mechanical properties of MMCs were investigated. In the present investigation, spheroidal graphite cast iron (GGG-40) was used as reinforcement material in bronze (CuSn10) matrix system. The MMCs were produced by hot press with 20 wt% GGG-40 reinforcement ratio. The total time required for the production of one specimen was selected as 25 min and temperature was settled at 400 degrees C. In order to determine mechanical properties and consolidation mechanism of MMCs, Brinell and micro-Vickers hardness, porosity, compression and X-ray diffraction tests were conducted. In addition, microstructure views were examined to determine the consolidation quality of metallic chips. According to experimental results, it was observed that waste metallic chips can be successfully recycled into MMC final parts with approximately 40% porosity and almost 100% strength and 150% hardness with respect to bulk CuSn10 materials. Most of the presented studies in the literature present information about properties of MMCs fabricated by conventional production methods. However, no available data are found about the recycling of bronze-based MMCs which make this study more original. It is also shown in this study that waste metallic chips can be utilized by proposed recycling methodology, which is environmentally friendly in comparison with conventional recycling methods producing harmful gases for earth atmosphere.