Browsing by Author "Eski Ö."

Now showing 1 - 2 of 2

The effect of CNT content and sintering temperature on some properties of CNT-reinforced MgAl composites
(2017-01-01) Islak S.; Küçük Ö.; Eski Ö.; Özorak C.; Akkaş M.
Magnesium and its alloys are considered as an important material for modern light structures at the present time and therefore they have a wide area of usage especially in electronics, aircraft, and automotive industries. Its popularity increases further as a result of its production as a composite material. In this study, carbon nanotube (CNT) reinforced MgAl matrix composite materials were produced by using the hot pressing method. While 0.25 wt%, 0.50 wt%, 0.75 wt%, and 1.00 wt% CNT were added, 450°C, 500°C, and 550°C was selected as sintering temperatures. The effect of sintering temperature and amount of CNT on some properties of the composites was examined. Microstructure and phase composition of the materials were examined by using optical microscopy (OM), scanning electron microscope (SEM), X-ray diffraction (XRD), and energy-dispersive X-ray spectroscopy (EDS). The hardness of the composites was measured in Brinell. Relative densities of the materials were determined in accordance with Archimedes’ principle. A dense and slightly porous structure was obtained based on both SEM images and density measurements. XRD analyses showed that there were Mg, Mg17Al12, and MgO phases in the composites. The reason for the absence of Al in graphics was that Al formed the solid solution by being dissolved in Mg. Also, the C peak could not be determined for CNT. The hardness of the composites increased with the increasing sintering temperature and CNT addition. The highest hardness value was measured as 88.45 HB10 with the addition of 1.00 wt% CNT at 550°C. Free distribution of CNT in the matrix caused this hardness increase.
Wear properties and synthesis of crfenimoti high entropy alloy coatings produced by TIG process
(2020-06-01) Islak S.; Eski Ö.; Koç V.; Özorak C.
The aim of this study is to investigate wear and microstructure properties of CrFeNiMoTi high entropy alloy coating produced by using tungsten inert gas (TIG) process on the medium carbon steel. The coatings have been compared in terms of their phase composition, microstructure, and hardness. Phase compound and microstructure of coating layers have been examined by using X-ray diffractometer (XRD), scanning electron microscope (SEM), and optical microscope (OM). The images show that the coatings have consisted of the cladding zone, interface zone, and heat affected zone. Also, the microstructure of the coating has been mainly composed of dendrite and discontinuous interdendritic segregation. The surface microhardness of this high entropy alloys up to 450 HV0.3, has been about 2.5 times as the substrate. The wear behaviour of the specimens has been compared through dry sliding wear tests under the same conditions. Average coefficient of friction values of the high entropy alloy (HEA) coating has been obtained at relatively low levels.