Yazar "Guder, H. Salih" seçeneğine göre listele

Listeleniyor 1 - 4 / 4
  • Küçük Resim
    Öğe
    Hardness Behavior of Alumina-Zirconia Nanocomposites Synthesized by Gel Process
    (Polish Acad Sciences Inst Physics, 2013) Sahin, O.; Hasde, A.; Gocmez, H.; Tuncer, M.; Cetinkara, H. Ali; Guder, H. Salih; Sahin, E.
    The alumina-zirconia composites are one of the relatively good and promising candidates for biomaterials application, due to biocompatibility and their mechanical properties that combines high flexural strength with a high toughness. The aim of the present work is to analyze the mechanical properties of these composites, where zirconia content was varied from 5 to 50 wt%. The citrate gel method, similar to the polymerized complex method, was used to synthesize these ceramics. Scanning electron microscopy, X-ray diffraction and microhardness tests are used to characterize synthesized materials. The examined material exhibits the behaviour of indentation size effect. Modified proportional resistance model are used to analyze the load dependence of the microhardness. X-ray diffraction analysis was used to calculation of the grain size and dislocation density. It is found that hardness is decreased when the zirconia content increases with enlargement of grain size. DOI: 10.12693/APhysPolA.123.299
  • Küçük Resim
    Öğe
    Mechanical Properties of Nanocrystalline Tetragonal Zirconia Stabilized with CaO, MgO and Y2O3
    (Polish Acad Sciences Inst Physics, 2013) Sahin, O.; Demirkol, I.; Gocmez, H.; Tuncer, M.; Cetinkara, H. Ali; Guder, H. Salih; Sahin, E.
    The citrate gel method, similar to the polymerized complex method, was used to synthesize homogeneous tetragonal zirconia at 1000 degrees C. Nanocrystalline tetragonal phase has been fully stabilized at wide temperature range with 10 mol.% CaO, MgO, and Y2O3 addition. Scanning electron microscopy, X-ray diffraction, and microhardness tests are used to characterize synthesized materials. The grain size and dislocation density were calculated from X-ray diffraction data. The examined material exhibits indentation size effect behavior. Results revealed that the Vickers and Knoop microhardness are dependent on indentation test load. Geometrically necessary dislocation model and modified proportional resistance model are used to analyze the load dependence of the microhardness. The highest hardness values were obtained for the samples with CaO addition; however the lowest values were acquired for sample stabilized with Y2O3 by using both Knoop and Vickers techniques. This situation might be explained using the Hall-Fetch relation. DOI: 10.12693/APhysPolA.123.296
  • Küçük Resim
    Öğe
    Production and Mechanical Behaviour of Biomedical CoCrMo Alloy
    (Iop Publishing Ltd, 2011) Sahin, O.; Tuncdemir, A. Riza; Cetinkara, H. Ali; Guder, H. Salih; Sahin, E.
    Cobalt-based alloy (Co-30Cr-5.5Mo) is produced by the investment casting process. This alloy complies with the ASTM F75 standard and is widely used in the manufacturing of orthopedic implants because of its high strength, good corrosion resistance and excellent biocompatibility properties. SEM, XRD and microhardness tests are used to examine the mechanical properties of the material. The examined material exhibits the behaviour of indentation size effect (ISE). Our results reveal that Vickers and Knoop microhardness are dependent on indentation test load. The traditional Meyer's law, the proportional specimen resistance (PSR) model and the Hays-Kendall model (HK) are used to analyze the load dependence of the hardness. As a result, the Hays-Kendall model is found to be the most effective to determine the load-independent hardness H-LI of CoCrMo alloy.
  • [ N/A ]
    Öğe
    Temporal Variability in Abundance of Demersal Fish Community from Izmir Bay, Turkey
    (Medwell Online, 2009) Can, M. Fatih; Tosunoglu, Zafer; Ozaydin, Okan; Demirci, Aydin; Guder, H. Salih; Aydin, Celalettin; Leblebici, Semih
    Temporal variabilities of demersal fish species were analaysed in terms of their numerical abundance in the Izmir Bay. A total of 545559 specimen belonging to eight different families were caught in 2005, covering all the year using a R/V trawl. The contribution of each family was Sparidae (34.38%), Serranidae (22.25%), Bothidae (15.09%), Mullidae (14.22%), Gobidae (3.71%), Centracanthidae (1.01%) and Uranoscopidae (0.28%). Based on temporal variabilities of the families, cluster analysis identified three main groups, which were group-I: the Mullidae, group-II: the Centracanthidae, Uranoscopidae, Bothidae, Gobidae and Serranidae and finally group-III: the Sparidae and Triglidae. The family belonging to the first group was more abundant in cold months (picked in January) than others. The second group were more yielded in general from June-October (picked in October). The third group were more abundant in May and June.