feray guleryuz | Ege University (original) (raw)
Papers by feray guleryuz
Hacettepe Journal of Biology and Chemistry, Aug 1, 2022
Y ük dengesine dikkate alınarak, trivalent disprosyum katkılı Cd 1-x Ta 2 O 6 :xDy 3+ (x=%0.5, 1,... more Y ük dengesine dikkate alınarak, trivalent disprosyum katkılı Cd 1-x Ta 2 O 6 :xDy 3+ (x=%0.5, 1, 2, 3, 5 at) fosfor serisi katı hal reaksiyonu yolu ile 1100 o C 'de 8 saat süreyle üretilmiştir. Sentezlenen fosforlar XRD (X-ışını kırınımı), SEM (taramalı elektron mikroskobu) ve PL (fotolüminesans) analizleri ile incelenmiştir. XRD ve SEM analizleri ortorombik kolombit kristal yapısını ve sırasıyla mikron altı ve birkaç mikron tane boyutuna sahip oval benzeri ve şekilsiz morfolojinin varlığını ortaya çıkardı. 387.8 nm'lik uyarım ile fosforlar, Dy 3+ 'nin 4 F 9/2 → 6 H 15/2 and 4 F 9/2 → 6 H 13/2 geçişlerine bağlı olarak sırasıyla 482.4 nm ve 578.5 nm'de mavi ve sarı emisyonlar sergilediler. Kadmiyum tantalat fosforun emisyon şiddeti Dy 3+ konsantrasyonu ile x=%5 at değerine kadar artarken emisyon şiddetinin azaltan konsantrasyon söndürme gerçekleşmemiştir. Konsantrasyon söndürmenin meydana gelmemesinin sebebi yük dengesindeki iyileşme nedeniyle yapısal kusurların azalması ve uyarma enerjisinin ışınımsız geçişlere dönüşümünün azalmasına bağlanabilir. Cd 1-x Ta 2 O 6 :xDy 3+ (x=%0.5, 1, 2, 3, 5 at) fosforlarının Commission Internationale d'Eclairage (CIE) koordinatları kromatiklik diyagramında beyaz bölgenin yakınında bulunmuştur.
Journal of the Turkish Chemical Society, Section A: Chemistry, Feb 28, 2023
Cd1-xTa2O6:xNd 3+ (x=0.5, 1.5, 3, 5, 7, and 10 mol%) phosphor series were fabricated by conventio... more Cd1-xTa2O6:xNd 3+ (x=0.5, 1.5, 3, 5, 7, and 10 mol%) phosphor series were fabricated by conventional solid state method at 1100 °C for 17 hours. The samples of cadmium tantalate were investigated by structural (XRD, SEM) and spectroscopic (CL, PL) analyses. In XRD results, the symmetry of CdTa2O6 phase with orthorhombic columbite structure was confirmed between 0.5 and 10 mol% Nd 3+ doping concentrations. SEM analysis of the grains revealed round and shapeless morphology while grain sizes ranged from submicron to several microns. The emission spectra of Cd1-xTa2O6:xNd 3+ (x=0.5, 1.5, 3, 5, 7 and 10 mol%) phosphor series recorded with the transitions of 4 F3/2→ 4 I9/2 and 4 F3/2→ 4 I11/2. Among these transitions, the transition 4 F3/2→ 4 I9/2 (at 889 nm) has a high near-infrared emission intensity, which can be attributed to the laser potential of the phosphor. The NIR emission of the phosphor increased with increasing concentration of Nd 3+ up to 5 mol% and then declined because of concentration quenching phenomenon. The CL emission peak at about 450 nm found in all samples is related to the intrinsic emission of the cadmium tantalate host. In addition, Nd 3+ doped phosphors exhibited the 4 F3/2→ 4 I9/2 transition of Nd 3+ and defect-related CL emissions at 670 nm. Decreasing crystallinity with increasing Nd 3+ concentration caused a decrease in host emission intensity at 450 nm.
Journal of the Turkish Chemical Society, Section A: Chemistry, Jun 23, 2023
Trivalent Eu-activated CoNb2O6 phosphors were fabricated using the molten salt method, which prov... more Trivalent Eu-activated CoNb2O6 phosphors were fabricated using the molten salt method, which provides enhanced homogeneity and low sintering temperature. The ceramic samples were examined by spectral and structural analyses. In X-ray diffractions, the single phase of orthorhombic columbite type CoNb2O6 structure was obtained for 0.5-10 mol% Eu3+ doping concentrations, while a two theta peak shift towards the smaller angles occurred. SEM examinations show an irregular morphology and sub-micron grain sizes. In photoluminescence (PL) spectra, the phosphors showed typical Eu3+ emissions with the 5F0 → 7FJ (J=0, 1, 2, 3, 4) transitions, and high emission peaks were observed at the 5D0 → 7F2 transition. The photoluminescence of CoNb2O6:Eu3+ decreased over 5 mol% because of the concentration quenching. The energy transfer mechanism and critical distance of the phosphor are the dipole-dipole (d–d) interaction, and 15.70 Å, respectively. The spectral features of the phosphors were assessed by calculating the Judd-Ofelt intensity parameters (Ω2, Ω4) from the PL emission spectrum. The low Ω2 parameter values or/and the Ω4>Ω2 trend for CoNb2O6:Eu3+ phosphors were related to the less covalent or more ionic character of the Eu3+–O2˗ bond and the high local symmetry of the Eu3+ sites, while the high Ω4 parameter values may be ascribed to the decrease in the electron density in the ligands.
Optik, 2017
Undoped, 0.5, 3 and 6 mol% Dy 3+ doped CoNb 2 O 6 powders have been prepared by molten salt metho... more Undoped, 0.5, 3 and 6 mol% Dy 3+ doped CoNb 2 O 6 powders have been prepared by molten salt method using cobalt nitrate hexa hydrate, niobium oxide, dysprosium oxide and Li 2 SO 4 Na 2 SO 4 salt mixture as a flux at 800 • C for 4 h. X-ray diffraction patterns of the undoped, 0.5 and 3 mol% doped CoNb 2 O 6 samples exhibited a single orthorhombic columbite phase, while 6 mol% Dy 3+ doped powder showed minor phase. SEM-EDS results coonfirmed XRD findings and revealed smaller grain size by increasing Dy 3+ concentration. Structural and luminescence properties of Dy 3+ doped samples in UV-vis spectral region were studied. The emissions increased with increasing doping concentration up to 3 mol%, and then decreased due to concentration quenching effect. The color chromaticity temperature (CCT) data of all samples have been estimated in white light region and color of light appear close to yellowish-green.
Journal of Alloys and Compounds, Apr 1, 2022
RSC Advances
In the study, the effect of boron doping on spectral properties and CTB mechanism was investigate... more In the study, the effect of boron doping on spectral properties and CTB mechanism was investigated by using Eu3+ doped orthorhombic β-SrTa2O6.
Journal of Materials Science: Materials in Electronics, Jun 25, 2022
Nucleation and Atmospheric Aerosols, 2012
ABSTRACT The purpose of this study is to define the effects of wire electrical discharge machinin... more ABSTRACT The purpose of this study is to define the effects of wire electrical discharge machining (WEDM) process parameters on surface roughness for Al/B4Cp metal matrix composites (MMCs) having different amounts of reinforcement particle (3, 6, and 12 wt.%). Totally nine experiments were performed according to the experimental design method conducted by Taguchi L-9 orthogonal array on Al/B4Cp MMC samples to determine the effect of WEDM process parameters on the surface roughness. The particle reinforcement amount (wt.%) is the most dominant factor (60.69%) on the surface roughness and it is followed by pulse on time (36.28%) and wire feed (1.49%), respectively. The surface roughness value taken from confirmation experiments and predicted value is 5.26 mu m, 5.37 mu m respectively.
Acta Physica Polonica A, Feb 1, 2013
In this study, the laser milling process was used to investigate the machinability of particle re... more In this study, the laser milling process was used to investigate the machinability of particle reinforced aluminum matrix composites manufactured by powder metallurgy having dierent amount of SiCp (5, 10, 20 wt%). In this context, the laser parameters like scan speed and ll spacing were associated with the SiCp amount in aluminum (Al) matrix. According to the experimental results, the scan speed is dominant factor on both milling depth and surface roughness. Also, the reinforcement particle amount (wt%) is the eective factor but there is no detected signicant relation between the surface roughness and reinforcement particle amount. However, the change in milling depth has been linearly changed with the increase of reinforcement particle amount.
International Journal of Surface Science and Engineering, 2012
Particle reinforced magnesium metal matrix composites (MMCs) and related manufacturing methods ar... more Particle reinforced magnesium metal matrix composites (MMCs) and related manufacturing methods are among important research topics because of their low density, high specific stiffness, strength and wear resistance. SiC p /Mg composites are commonly used materials for fabrication of lightweight functional components. Magnesium powders with mean size of 69 μm were used as raw material while reinforcement material was selected as SiC p with the average particle size of 84 μm. Different amounts of SiC p (3, 6, and 9 wt. %) were added to the magnesium matrix and the composite materials were sintered in a vacuum furnace at 590°C. Structural characterisation of the produced composites was performed using several techniques such as scanning electron microscopy (SEM) and X-ray diffraction. The green density of the composite materials increased with SiC p addition. The hardness of the composites was found to be higher than the pure Mg. Reinforcement with 9 wt. % SiC p showed significant increase in the compressive strength of magnesium matrix composites.
Acta Physica Polonica A, Feb 1, 2013
In this study, electrical discharge machining process was performed to investigate the machinabil... more In this study, electrical discharge machining process was performed to investigate the machinability of Al/B4Cp metal matrix composites manufactured by powder metallurgy. For this, an experimental layout was conducted by using full factorial design. In the analysis, there are three parameters of which one is at three levels and the remaining are two levels. Totally, 48 experiments were carried out. The surface roughness (Ra) was increased with increasing the current (C), pulse-on-time (Ton), pulse-o-time (T off) and amount of particle (PR).
Acta Physica Polonica A, Feb 1, 2013
Currently some composite materials and related manufacturing methods especially particle reinforc... more Currently some composite materials and related manufacturing methods especially particle reinforced magnesium matrix composites are among important research topics because of their superior properties over monolithic metals. Mg-B4Cp is the commonly used composite material for fabrication of lightweight functional components. Wear behaviour of particle reinforced magnesium matrix composites play critical role for potential application in industries such as automotive and aerospace. In this study, the dry sliding wear behavior of particle reinforced magnesium matrix composites manufactured by powder metallurgy with dierent amount of B4Cp (3, 6, 9 wt%) addition is investigated. Wear tests are performed on a pin-on-disk conguration against SAE 1040 steel counter body under constant load and sliding speed. The wear behaviour of particle reinforced magnesium matrix composites was evaluated as a function of B4Cp amount (wt%). After the wear test, worn surface of the samples was examined by scanning electron microscopy for pointing out the wear mechanism.
SAE technical paper series, Apr 8, 2013
Acta Physica Polonica A, Feb 1, 2013
This paper investigates the eect of electrical discharge machining parameters on the surface roug... more This paper investigates the eect of electrical discharge machining parameters on the surface roughness as an alternative method for machining of Al/SiCp metal matrix composites produced with the powder metallurgy. Current, electrode type, pulse-on-time, particle reinforcement weight ratio and voltage were used as the process parameters. An experimental plan (L18) was constituted by using the Taguchi orthogonal design. Results of experiments showed that pulse-on-time (34%) and current (31.26%) is the most inuencing parameters. Besides this, the percentage contribution of particle reinforcement on the surface roughness is 6.71%.
Chemical Papers, Jul 31, 2022
Hacettepe Journal of Biology and Chemistry, Aug 1, 2022
S on yıllarda, Mg alaşımları, otomotiv ve havacılık endüstrileri alanında, monolitik metallere gö... more S on yıllarda, Mg alaşımları, otomotiv ve havacılık endüstrileri alanında, monolitik metallere göre üstün özellikleri nedeniyle, ağırlık tasarrufu sağlayan uygulamalar için büyük umut vaat etmektedir. Bu çalışmada, farklı sinterleme sıcaklıklarına (375°C, 400°C, 425°C, 450°C) sahip Mg-SiC alaşımlarının aşınma davranışları incelenmiştir. Ağırlıkça %10 SiC içeren Mg-SiC tozları mekanik olarak karıştırılıp alaşımlanmış ve ardından vakumlu argon atmosferi altında FAST ile sinterlenmiştir. Alaşımların sürtünme katsayısı, sertlik değeri ve aşınma direnci saf Mg'den daha yüksektir. Sinterleme sıcaklığının 425°C'ye kadar artması, Mg-SiC alaşımlarının sürtünme katsayısının artmasına ve aşınma kütlesi kaybının azalmasına neden olmuştur.
Powder Metallurgy and Metal Ceramics, Nov 1, 2012
Due to their excellent properties such as high specific stiffness, strength/weight ratio, and wea... more Due to their excellent properties such as high specific stiffness, strength/weight ratio, and wear resistance, metal matrix composites (MMCs) with particulate reinforcement and related manufacturing methods have become important research topics in recent years. Magnesium MMCs are materials that are commonly used for fabrication of light-weight functional components. Magnesium MMCs that are reinforced with various fractions of B4C (3, 6, and 9 wt.%) were fabricated by powder metallurgy (PM) technique using a sintering cycle in a vacuum furnace at 590°C for 9 h. A qualitative analysis of X-ray diffraction (XRD) patterns indicated the formation of Al2O3, MgO, and MgB2 phases in the structure of Mg/B4C MMCs. The sintered density of the MMCs decreased with an increase in the amount of B4C addition. The hardness of the MMCs was found to be higher than that of unreinforced Mg. The compressive test results also showed a significant effect of 3 wt.% B4C content on the compressive strength of magnesium MMCs manufactured by the PM technique.
AIP Conference Proceedings, 2017
The objective of the innovative approaches of the scintillation materials to be used in the digit... more The objective of the innovative approaches of the scintillation materials to be used in the digital portal imaging systems in the radiotherapy applications is to research the GOS material production that has been activated with the rare earth elements (RE), to produce the scintillation detectors that have a rapid imaging process with a lesser radiation and higher image quality from these materials and to apply the radiographic imaging systems. The GOS: Tb 3+ showed high emission peak and high x-ray absorption properties which have been determined for application to mammography and dental radiography. In this study, Gd2O2SO4:Tb 3+ phosphors were fabricated by the sol-gel method that is a unique technique and not previously applied. Besides, the structural characterization of GOS: Tb 3+ has been investigated. The strongest emission peak located at 549 nm under 312 nm UV light excitation was appeared on the GOS: Tb 3+ phosphor particles. The characterization processing optimized by using FTIR, DTA-TG, XRD, XPS, SEM and the luminescence spectroscopy.
AIP Conference Proceedings, 2017
Radiographic imaging which transforms y or x rays into visible light is one of the most important... more Radiographic imaging which transforms y or x rays into visible light is one of the most important developments in the field of digital imaging systems in recent years. Materials consisting of rare earth elements have strong scintillation properties in digital radiology. Gd2O2SO4 is studied due to having effective magnetic properties and excellent luminescence spectra. Additionally, Gd2O2SO4:Eu 3+ has thermal stability and ideal red light emission performance with peak emission at around 618 nm when activated under X-ray or ultraviolet light. In this study, Gd2O2SO4:Eu 3+ nanoparticles were synthesized by sol-gel method and were calcined at 950 o C in argon gas atmosphere. In the analysis of the produced nanoparticles XRD, SEM, XPS and optical luminescence devices were used to evaluate the results.
Acta Physica Polonica A, 2017
Scintillation materials are widely used in digital X-ray imaging applications, radiotherapy appli... more Scintillation materials are widely used in digital X-ray imaging applications, radiotherapy applications coupled with suitable photoreceptors. Gd2O2SO4 (GOS) scintillator doped with trivalent praseodymium (Pr 3+) presented high X-ray absorption properties and good spectral compatibility which were utilized extensively for imaging system of X-ray microscopy, soft X-ray phosphor screen for water window. In this study, GOS:0.01Pr 3+ scintillation material was synthesized by unique sol-gel process which was not previously applied and its characterization properties were investigated. Structure and luminescence properties of GOS:Pr 3+ were optimized by utilizing X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, and luminescence spectroscopy.
Hacettepe Journal of Biology and Chemistry, Aug 1, 2022
Y ük dengesine dikkate alınarak, trivalent disprosyum katkılı Cd 1-x Ta 2 O 6 :xDy 3+ (x=%0.5, 1,... more Y ük dengesine dikkate alınarak, trivalent disprosyum katkılı Cd 1-x Ta 2 O 6 :xDy 3+ (x=%0.5, 1, 2, 3, 5 at) fosfor serisi katı hal reaksiyonu yolu ile 1100 o C 'de 8 saat süreyle üretilmiştir. Sentezlenen fosforlar XRD (X-ışını kırınımı), SEM (taramalı elektron mikroskobu) ve PL (fotolüminesans) analizleri ile incelenmiştir. XRD ve SEM analizleri ortorombik kolombit kristal yapısını ve sırasıyla mikron altı ve birkaç mikron tane boyutuna sahip oval benzeri ve şekilsiz morfolojinin varlığını ortaya çıkardı. 387.8 nm'lik uyarım ile fosforlar, Dy 3+ 'nin 4 F 9/2 → 6 H 15/2 and 4 F 9/2 → 6 H 13/2 geçişlerine bağlı olarak sırasıyla 482.4 nm ve 578.5 nm'de mavi ve sarı emisyonlar sergilediler. Kadmiyum tantalat fosforun emisyon şiddeti Dy 3+ konsantrasyonu ile x=%5 at değerine kadar artarken emisyon şiddetinin azaltan konsantrasyon söndürme gerçekleşmemiştir. Konsantrasyon söndürmenin meydana gelmemesinin sebebi yük dengesindeki iyileşme nedeniyle yapısal kusurların azalması ve uyarma enerjisinin ışınımsız geçişlere dönüşümünün azalmasına bağlanabilir. Cd 1-x Ta 2 O 6 :xDy 3+ (x=%0.5, 1, 2, 3, 5 at) fosforlarının Commission Internationale d'Eclairage (CIE) koordinatları kromatiklik diyagramında beyaz bölgenin yakınında bulunmuştur.
Journal of the Turkish Chemical Society, Section A: Chemistry, Feb 28, 2023
Cd1-xTa2O6:xNd 3+ (x=0.5, 1.5, 3, 5, 7, and 10 mol%) phosphor series were fabricated by conventio... more Cd1-xTa2O6:xNd 3+ (x=0.5, 1.5, 3, 5, 7, and 10 mol%) phosphor series were fabricated by conventional solid state method at 1100 °C for 17 hours. The samples of cadmium tantalate were investigated by structural (XRD, SEM) and spectroscopic (CL, PL) analyses. In XRD results, the symmetry of CdTa2O6 phase with orthorhombic columbite structure was confirmed between 0.5 and 10 mol% Nd 3+ doping concentrations. SEM analysis of the grains revealed round and shapeless morphology while grain sizes ranged from submicron to several microns. The emission spectra of Cd1-xTa2O6:xNd 3+ (x=0.5, 1.5, 3, 5, 7 and 10 mol%) phosphor series recorded with the transitions of 4 F3/2→ 4 I9/2 and 4 F3/2→ 4 I11/2. Among these transitions, the transition 4 F3/2→ 4 I9/2 (at 889 nm) has a high near-infrared emission intensity, which can be attributed to the laser potential of the phosphor. The NIR emission of the phosphor increased with increasing concentration of Nd 3+ up to 5 mol% and then declined because of concentration quenching phenomenon. The CL emission peak at about 450 nm found in all samples is related to the intrinsic emission of the cadmium tantalate host. In addition, Nd 3+ doped phosphors exhibited the 4 F3/2→ 4 I9/2 transition of Nd 3+ and defect-related CL emissions at 670 nm. Decreasing crystallinity with increasing Nd 3+ concentration caused a decrease in host emission intensity at 450 nm.
Journal of the Turkish Chemical Society, Section A: Chemistry, Jun 23, 2023
Trivalent Eu-activated CoNb2O6 phosphors were fabricated using the molten salt method, which prov... more Trivalent Eu-activated CoNb2O6 phosphors were fabricated using the molten salt method, which provides enhanced homogeneity and low sintering temperature. The ceramic samples were examined by spectral and structural analyses. In X-ray diffractions, the single phase of orthorhombic columbite type CoNb2O6 structure was obtained for 0.5-10 mol% Eu3+ doping concentrations, while a two theta peak shift towards the smaller angles occurred. SEM examinations show an irregular morphology and sub-micron grain sizes. In photoluminescence (PL) spectra, the phosphors showed typical Eu3+ emissions with the 5F0 → 7FJ (J=0, 1, 2, 3, 4) transitions, and high emission peaks were observed at the 5D0 → 7F2 transition. The photoluminescence of CoNb2O6:Eu3+ decreased over 5 mol% because of the concentration quenching. The energy transfer mechanism and critical distance of the phosphor are the dipole-dipole (d–d) interaction, and 15.70 Å, respectively. The spectral features of the phosphors were assessed by calculating the Judd-Ofelt intensity parameters (Ω2, Ω4) from the PL emission spectrum. The low Ω2 parameter values or/and the Ω4>Ω2 trend for CoNb2O6:Eu3+ phosphors were related to the less covalent or more ionic character of the Eu3+–O2˗ bond and the high local symmetry of the Eu3+ sites, while the high Ω4 parameter values may be ascribed to the decrease in the electron density in the ligands.
Optik, 2017
Undoped, 0.5, 3 and 6 mol% Dy 3+ doped CoNb 2 O 6 powders have been prepared by molten salt metho... more Undoped, 0.5, 3 and 6 mol% Dy 3+ doped CoNb 2 O 6 powders have been prepared by molten salt method using cobalt nitrate hexa hydrate, niobium oxide, dysprosium oxide and Li 2 SO 4 Na 2 SO 4 salt mixture as a flux at 800 • C for 4 h. X-ray diffraction patterns of the undoped, 0.5 and 3 mol% doped CoNb 2 O 6 samples exhibited a single orthorhombic columbite phase, while 6 mol% Dy 3+ doped powder showed minor phase. SEM-EDS results coonfirmed XRD findings and revealed smaller grain size by increasing Dy 3+ concentration. Structural and luminescence properties of Dy 3+ doped samples in UV-vis spectral region were studied. The emissions increased with increasing doping concentration up to 3 mol%, and then decreased due to concentration quenching effect. The color chromaticity temperature (CCT) data of all samples have been estimated in white light region and color of light appear close to yellowish-green.
Journal of Alloys and Compounds, Apr 1, 2022
RSC Advances
In the study, the effect of boron doping on spectral properties and CTB mechanism was investigate... more In the study, the effect of boron doping on spectral properties and CTB mechanism was investigated by using Eu3+ doped orthorhombic β-SrTa2O6.
Journal of Materials Science: Materials in Electronics, Jun 25, 2022
Nucleation and Atmospheric Aerosols, 2012
ABSTRACT The purpose of this study is to define the effects of wire electrical discharge machinin... more ABSTRACT The purpose of this study is to define the effects of wire electrical discharge machining (WEDM) process parameters on surface roughness for Al/B4Cp metal matrix composites (MMCs) having different amounts of reinforcement particle (3, 6, and 12 wt.%). Totally nine experiments were performed according to the experimental design method conducted by Taguchi L-9 orthogonal array on Al/B4Cp MMC samples to determine the effect of WEDM process parameters on the surface roughness. The particle reinforcement amount (wt.%) is the most dominant factor (60.69%) on the surface roughness and it is followed by pulse on time (36.28%) and wire feed (1.49%), respectively. The surface roughness value taken from confirmation experiments and predicted value is 5.26 mu m, 5.37 mu m respectively.
Acta Physica Polonica A, Feb 1, 2013
In this study, the laser milling process was used to investigate the machinability of particle re... more In this study, the laser milling process was used to investigate the machinability of particle reinforced aluminum matrix composites manufactured by powder metallurgy having dierent amount of SiCp (5, 10, 20 wt%). In this context, the laser parameters like scan speed and ll spacing were associated with the SiCp amount in aluminum (Al) matrix. According to the experimental results, the scan speed is dominant factor on both milling depth and surface roughness. Also, the reinforcement particle amount (wt%) is the eective factor but there is no detected signicant relation between the surface roughness and reinforcement particle amount. However, the change in milling depth has been linearly changed with the increase of reinforcement particle amount.
International Journal of Surface Science and Engineering, 2012
Particle reinforced magnesium metal matrix composites (MMCs) and related manufacturing methods ar... more Particle reinforced magnesium metal matrix composites (MMCs) and related manufacturing methods are among important research topics because of their low density, high specific stiffness, strength and wear resistance. SiC p /Mg composites are commonly used materials for fabrication of lightweight functional components. Magnesium powders with mean size of 69 μm were used as raw material while reinforcement material was selected as SiC p with the average particle size of 84 μm. Different amounts of SiC p (3, 6, and 9 wt. %) were added to the magnesium matrix and the composite materials were sintered in a vacuum furnace at 590°C. Structural characterisation of the produced composites was performed using several techniques such as scanning electron microscopy (SEM) and X-ray diffraction. The green density of the composite materials increased with SiC p addition. The hardness of the composites was found to be higher than the pure Mg. Reinforcement with 9 wt. % SiC p showed significant increase in the compressive strength of magnesium matrix composites.
Acta Physica Polonica A, Feb 1, 2013
In this study, electrical discharge machining process was performed to investigate the machinabil... more In this study, electrical discharge machining process was performed to investigate the machinability of Al/B4Cp metal matrix composites manufactured by powder metallurgy. For this, an experimental layout was conducted by using full factorial design. In the analysis, there are three parameters of which one is at three levels and the remaining are two levels. Totally, 48 experiments were carried out. The surface roughness (Ra) was increased with increasing the current (C), pulse-on-time (Ton), pulse-o-time (T off) and amount of particle (PR).
Acta Physica Polonica A, Feb 1, 2013
Currently some composite materials and related manufacturing methods especially particle reinforc... more Currently some composite materials and related manufacturing methods especially particle reinforced magnesium matrix composites are among important research topics because of their superior properties over monolithic metals. Mg-B4Cp is the commonly used composite material for fabrication of lightweight functional components. Wear behaviour of particle reinforced magnesium matrix composites play critical role for potential application in industries such as automotive and aerospace. In this study, the dry sliding wear behavior of particle reinforced magnesium matrix composites manufactured by powder metallurgy with dierent amount of B4Cp (3, 6, 9 wt%) addition is investigated. Wear tests are performed on a pin-on-disk conguration against SAE 1040 steel counter body under constant load and sliding speed. The wear behaviour of particle reinforced magnesium matrix composites was evaluated as a function of B4Cp amount (wt%). After the wear test, worn surface of the samples was examined by scanning electron microscopy for pointing out the wear mechanism.
SAE technical paper series, Apr 8, 2013
Acta Physica Polonica A, Feb 1, 2013
This paper investigates the eect of electrical discharge machining parameters on the surface roug... more This paper investigates the eect of electrical discharge machining parameters on the surface roughness as an alternative method for machining of Al/SiCp metal matrix composites produced with the powder metallurgy. Current, electrode type, pulse-on-time, particle reinforcement weight ratio and voltage were used as the process parameters. An experimental plan (L18) was constituted by using the Taguchi orthogonal design. Results of experiments showed that pulse-on-time (34%) and current (31.26%) is the most inuencing parameters. Besides this, the percentage contribution of particle reinforcement on the surface roughness is 6.71%.
Chemical Papers, Jul 31, 2022
Hacettepe Journal of Biology and Chemistry, Aug 1, 2022
S on yıllarda, Mg alaşımları, otomotiv ve havacılık endüstrileri alanında, monolitik metallere gö... more S on yıllarda, Mg alaşımları, otomotiv ve havacılık endüstrileri alanında, monolitik metallere göre üstün özellikleri nedeniyle, ağırlık tasarrufu sağlayan uygulamalar için büyük umut vaat etmektedir. Bu çalışmada, farklı sinterleme sıcaklıklarına (375°C, 400°C, 425°C, 450°C) sahip Mg-SiC alaşımlarının aşınma davranışları incelenmiştir. Ağırlıkça %10 SiC içeren Mg-SiC tozları mekanik olarak karıştırılıp alaşımlanmış ve ardından vakumlu argon atmosferi altında FAST ile sinterlenmiştir. Alaşımların sürtünme katsayısı, sertlik değeri ve aşınma direnci saf Mg'den daha yüksektir. Sinterleme sıcaklığının 425°C'ye kadar artması, Mg-SiC alaşımlarının sürtünme katsayısının artmasına ve aşınma kütlesi kaybının azalmasına neden olmuştur.
Powder Metallurgy and Metal Ceramics, Nov 1, 2012
Due to their excellent properties such as high specific stiffness, strength/weight ratio, and wea... more Due to their excellent properties such as high specific stiffness, strength/weight ratio, and wear resistance, metal matrix composites (MMCs) with particulate reinforcement and related manufacturing methods have become important research topics in recent years. Magnesium MMCs are materials that are commonly used for fabrication of light-weight functional components. Magnesium MMCs that are reinforced with various fractions of B4C (3, 6, and 9 wt.%) were fabricated by powder metallurgy (PM) technique using a sintering cycle in a vacuum furnace at 590°C for 9 h. A qualitative analysis of X-ray diffraction (XRD) patterns indicated the formation of Al2O3, MgO, and MgB2 phases in the structure of Mg/B4C MMCs. The sintered density of the MMCs decreased with an increase in the amount of B4C addition. The hardness of the MMCs was found to be higher than that of unreinforced Mg. The compressive test results also showed a significant effect of 3 wt.% B4C content on the compressive strength of magnesium MMCs manufactured by the PM technique.
AIP Conference Proceedings, 2017
The objective of the innovative approaches of the scintillation materials to be used in the digit... more The objective of the innovative approaches of the scintillation materials to be used in the digital portal imaging systems in the radiotherapy applications is to research the GOS material production that has been activated with the rare earth elements (RE), to produce the scintillation detectors that have a rapid imaging process with a lesser radiation and higher image quality from these materials and to apply the radiographic imaging systems. The GOS: Tb 3+ showed high emission peak and high x-ray absorption properties which have been determined for application to mammography and dental radiography. In this study, Gd2O2SO4:Tb 3+ phosphors were fabricated by the sol-gel method that is a unique technique and not previously applied. Besides, the structural characterization of GOS: Tb 3+ has been investigated. The strongest emission peak located at 549 nm under 312 nm UV light excitation was appeared on the GOS: Tb 3+ phosphor particles. The characterization processing optimized by using FTIR, DTA-TG, XRD, XPS, SEM and the luminescence spectroscopy.
AIP Conference Proceedings, 2017
Radiographic imaging which transforms y or x rays into visible light is one of the most important... more Radiographic imaging which transforms y or x rays into visible light is one of the most important developments in the field of digital imaging systems in recent years. Materials consisting of rare earth elements have strong scintillation properties in digital radiology. Gd2O2SO4 is studied due to having effective magnetic properties and excellent luminescence spectra. Additionally, Gd2O2SO4:Eu 3+ has thermal stability and ideal red light emission performance with peak emission at around 618 nm when activated under X-ray or ultraviolet light. In this study, Gd2O2SO4:Eu 3+ nanoparticles were synthesized by sol-gel method and were calcined at 950 o C in argon gas atmosphere. In the analysis of the produced nanoparticles XRD, SEM, XPS and optical luminescence devices were used to evaluate the results.
Acta Physica Polonica A, 2017
Scintillation materials are widely used in digital X-ray imaging applications, radiotherapy appli... more Scintillation materials are widely used in digital X-ray imaging applications, radiotherapy applications coupled with suitable photoreceptors. Gd2O2SO4 (GOS) scintillator doped with trivalent praseodymium (Pr 3+) presented high X-ray absorption properties and good spectral compatibility which were utilized extensively for imaging system of X-ray microscopy, soft X-ray phosphor screen for water window. In this study, GOS:0.01Pr 3+ scintillation material was synthesized by unique sol-gel process which was not previously applied and its characterization properties were investigated. Structure and luminescence properties of GOS:Pr 3+ were optimized by utilizing X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, and luminescence spectroscopy.