Browsing by Author "Kilicaslan, MF, Karakose, E"

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Depth sensing indentation analyses of hypereutectic Al-10Ni — XSc (X = 0, 1, 2) alloys
(2017-05-01) Kilicaslan M.F., Karakose E.; Kilicaslan, MF, Karakose, E
Depth sensing indentation analyses of hypereutectic Al-10Ni alloys with different amounts of Sc content were performed to determine the values of elastic modulus, dynamic microhardness, creep rate and elastic recovery rate. Microstructural characterizations were performed by using scanning electron microscopy (SEM), SEM mapping and an X-ray diffractometer. The results revealed that the addition of Sc refined the intermetallic phases of Al and Ni, and led to the formation of two additional intermetallic phases as well, namely Al3Sc and metastable Al9Ni2. The Al-Ni alloys investigated in this work exhibited elastoplastic behavior at room temperature and the addition of Sc influences their elastic-plastic responses to the indentation process. In addition, dynamic microhardness of them exhibited a load-dependent character called the indentation size effect. The addition of Sc considerably improved the values of dynamic microharddness, elastic modulus and elastic recovery rate. It also resulted in a lower creep displacement rate.
Effect of Sc addition on the microstructure and mechanical properties OF MELT-SPUN Al-10Ni alloys
(2018-01-01) Fatih Kilicaslan M., Karakose E.; Kilicaslan, MF, Karakose, E
In the present work, rapidly solidified Al-10Ni-XSc (X = 0, 1 and 2) alloys were fabricated by melt spinning under Ar atmosphere. The Effects of Sc on the microstructural and thermal properties and microhardness values were investigated by scanning electron microscopy (SEM), X-ray diffractometer (XRD) and a Vickers microhardness tester. Experimental results revealed that the addition of 2 wt. % Sc to melt-spun Al-10Ni alloys changed their brittle nature and hindered formation of cracks. The addition of Sc to melt-spun Al-10Ni alloys also changed the morphology of Al3Ni intermetallics from an acicular/needle – like to a rounded particle-like structure and led to reduction in their size. Formation of the metastable Al9Ni2 phase was observed due to the higher constitutional undercooling caused by Sc addition. A considerable improvement in microhardness value (from 95. 9 to 230. 1 HV) was observed with the addition of Sc.
Production of CNT-bearing melt-spun Al-2Sc-0.05CNT alloys
(2018-03-25) Kilicaslan M.F., Karaköse E.; Kilicaslan, MF, Karakose, 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.