Browsing by Author "Karaköse E."
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Scopus Formation of novel rice-like intermetallic phases and changes in the mechanical, microstructural and electrical properties of Sn-5Sb alloys with addition Ag and Bi(2016-01-15) Karaköse E.; Kiliçaslan M.; Çolak H.In the present study, the effects of Ag and Bi additions (1 wt.%) on the microstructural, thermal, mechanical and electrical properties of Sn-5Sb solder alloys were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), differential scanning calorimetry (DSC), microhardness tests, and four probe measurements. It was observed that the melting point of Sn-5Sb solder alloy decreased with the addition of Ag and Bi. It was found that the final microstructure of rapidly solidified Sn-5Sb-1X (X = Ag and Bi) alloys was strictly dependent upon the wheel speeds; the microstructures changed from a coarse dendritic and needle-like structure to a refined ultra fine dendritic and rice-like structure with increasing wheel speed. Cooling rate was also effective on both the mechanical and electrical properties. It was found that all of the alloys exhibit higher mechanical properties with increasing cooling rate and/or decreasing testing temperature. Similarly, significant improvements of 32% and 9% in electrical conductivity of both of the alloys were obtained with the addition of Ag and Bi, respectively. The microstructural evolution of the Sn-5Sb based alloys plays a crucial role in influencing the mechanical properties of these alloys.Scopus Production of CNT-bearing melt-spun Al-2Sc-0.05CNT alloys(2018-03-25) Kilicaslan M.F.; Karaköse E.In the present work, rapidly solidified Al–2Sc-XCNT (X = 0, 0.05) alloys were successfully fabricated by melt spinning under Ar atmosphere. The effects of addition of CNT on the microstructural, thermal, microhardness, and electrical properties were investigated by using scanning electron microscopy (SEM), X-ray diffractometer (XRD), differential calorimeter (DSC), Vickers microhardness testing and a four point probe resistivity tester. Experimental results illustrated that the addition of 0.05 wt% CNT to melt-spun Al–2Sc alloys led to the formation of equiaxed globular-like morphologies with size from 0.3 to 2.7 μm in. In the microstructure of Al-2Sc-0.05CNT alloy, CNTs covered by Al with size (width and length) changing from 40 to 55 nm and 255–295 nm, respectively, were observed. The addition of CNT led to a net increment (∼25%) in microhardness values due to solitary strengthening of the carbon nanotubes, solute solution hardening and modification of the morphologies of Al3Sc intermetallics. In addition, because of CNT addition there was a decrease in the electrical resistivity.