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Öğe Ca and Ce Effect on the Corrosion Resistance of Hot-Rolled AZ31 Mg Alloys(Dr D. Pylarinos, 2020) Kara, I.H.; Ahlatci, H.; Issa, Yousef, T.A.; Turen, Y.In this study, AZ31 Mg alloys with added Ca and Ce were produced by low pressure die casting and were rolled at 400°C. The corrosion properties of the materials were determined by immersion test for 72 hours at a 3.5% NaCl solution. The microstructure of the samples was investigated by light optical microscopy (LOM) and scanning electron microscopy (SEM) before the corrosion test. Twins, dynamic recrystallization (DRX), and the alloying elements have an important role in imparting the final corrosion resistance of the investigated materials. © 2020, Dr D. Pylarinos. All rights reserved.Öğe Development of Aluminum Alloy AA5754 Production with a Different Magnesium Content by a Twin-Roll Casting Process(Springer, 2015) Turbalioglu, K.; Sun, Y.; Turen, Y.The effect of magnesium content and different thermomechanical treatment regimes on structure formation for sheet aluminum alloy AA5754 produced by twin-roll casting technology is evaluated. Cast sheets of alloy AA5754 containing 2.8, 3.0, and 3.2 wt.% magnesium 6 mm thick are cold rolled to a thickness of 1 mm. Three thermomechanical treatment regimes and annealing for alloy AA5754 are studied. Specimens obtained by this technology are strength tested. Grain size and distribution within the structure of finished sheet workpieces are determined by a standard procedure. With an increase in magnesium content in specimen grain diameter is considerably reduced. All specimens, prepared by a supplementary production scheme using homogenizing heat treatment in the final annealing stage, have maximum ductility, and also higher values of ultimate and yield strength than for specimens prepared using other production schemes and changed magnesium content.Öğe Effect of Ca and Ce on Wear Behavior of Hot-Rolled AZ31 Mg Alloys(Polish Acad Sciences Inst Physics, 2020) Kara, I. H.; Yousef, T. A. I.; Ahlatci, H.; Turen, Y.In this study, Ca and Ce added AZ31 Mg alloys were produced by low pressure die casting method and the following materials were rolled at 400 degrees C. The wear properties of materials were investigated by wear test method according to ASTM-G133 in a dry condition at room temperature. The microstructure of samples investigated by light optical microscopy and scanning electron microscopy both before and after corrosion tests. The twins and dynamic recrystallization (DRX) and the alloying elements play an important role to impart the final wear resistance of investigated materials.Öğe Effect of indium addition on microstructure and mechanical properties of AS-CAST and hot-rolled AM60 magnesium alloy(TANGER Ltd., 2017) Zengin, H.; Turen, Y.; Ahlatci, H.; Sun, Y.In this study, effect of indium (In) addition on microstructure and mechanical properties of AM60 magnesium alloys was investigated. In additions were made by 0.2, 0.5 and 1 wt.%. Alloys were produced by conventional gravity casting in a steel mould. A homogenization treatment at 350 °C for 24 h was performed after casting processes. Homogenized samples were 1 pass hot-rolled by 40 % thickness reduction at 350 °C. The results showed that the average grain size of as-cast and hot-rolled AM60 alloys decreased with In addition. SEM analysis revealed that In addition led to formation of tiny Mg-In binary second phases at triple junctions. Tensile strength of as-cast AM60 alloy increased with increasing amount of In up to 0.5 wt.% above which it decreased. However, after hot-rolling process, AM60 alloy containing 0.2 wt.% In showed the best tensile properties. These improvements were attributed to the refinement of microstructure and dispersion strengthening by Mg- In intermetallic phases. © 2017 TANGER Ltd., Ostrava.Öğe Effect of Lanthanum on the Microstructure and Mechanical Properties of Hot-Rolled Magnesium Alloy AZ31(Springer, 2019) Kara, I. H.; Ahlatci, H.; Turen, Y.; Sun, Y.The effect of lanthanum additions (0.2 - 1.0%) on the microstructure and mechanical properties of magnesium alloy AZ31 is studied after hot rolling with deformation of 15 and 30%. The microstructure is analyzed by the methods of x-ray diffractometry, optical microscopy and scanning electron microscopy. The mean values of the ultimate strength, elongation and contraction are determined in tensile tests.Öğe Effect of Magnesium Additions on Composites with Al and Al-12% Si Matrices Strengthened with B4C and Prepared by Infiltration Under Pressure(Springer, 2016) Cevik, E.; Sun, Y.; Ahlatci, H.; Turen, Y.Metallographic and x-ray phase analyses are used for metal-matrix composites Al - B4C and (Al - 12% Si) - B4C with a volume fraction of 60% boron carbide prepared by infiltrating a pressed workpiece with metal under pressure. It is shown that with introduction of 1 to 4% Mg into a metal matrix composite porosity is reduced from 7 to 1%.Öğe Effect of sn addition on corrosion properties of As-Cast and Hot-Rolled AZ31 magnesium alloys(Trans Tech Publications Ltd, 2017) Turen, Y.; Guzel, D.; Zengin, H.; Sun, Y.; Ahlatci, H.In this study, the effect of Sn addition on corrosion resistance of as-cast and hot rolled AZ31 magnesium alloy was investigated. Sn additions were made by 0.2 wt%, 0.5 wt% and 1 wt%. An electric resistance furnace was used to produce alloys. Hot rolling process was performed at 350 °C by 40% thickness reduction at one rolling pass. Microstructure characterizations were performed by optical (OM) and scanning electron microscope (SEM). Immersion tests and electrochemical analyses were performed to investigate the corrosion resistance of the alloys. A 3.5% NaCl working solution at room temperature was used in both corrosion tests. The results showed that Sn addition decreased the primary dentrite size and restricted the growth of secondary dentritic arm. The as-cast structures transformed to dynamically recrystallized grain structures after hot-rolling process in all the alloys. Corrosion resistance of AZ31 magnesium alloy tended to decrease with Sn addition. This decrease was more clear in homogenized and hot-rolled states while there were some flactuations in as-cast states. © 2017 Trans Tech Publications, Switzerland.Öğe Effect of Ti addition on corrosion properties of As-Cast and Hot-rolled AM60 magnesium alloys(Trans Tech Publications Ltd, 2017) Sun, Y.; Aydin, N.U.; Turen, Y.; Ahlatci, H.; Zengin, H.This study investigates the effect of Ti addition (0.2, 0.5, 1wt%) on corrosion resistance of as-cast and hot rolled AM60 magnesium alloy. The results showed that Ti addition resulted in an alteration of the microstructure of as-cast AM60 magnesium alloy by decreasing the amount of-Mg17Al12 eutectic phase. Homogenization treatment resulted in the dissolution of the most of the-Mg17Al12 phases. Corrosion behaviors were investigated by immersion tests and electrochemical analysis. Homogenized samples exhibited the lowest corrosion rate in immersion test while the best corrosion resistance was found for hot-rolled samples in electrochemical test. In hot-rolled state, Ti addition led to a slight change in the corrosion behaviour of AM60 magnesium alloy. © 2017 Trans Tech Publications, Switzerland.Öğe Effects of bismuth (bi) additions on microstructure and mechanical properties of AZ91 alloy(TANGER Ltd., 2015) Elen, L.; Zengin, H.; Turen, Y.; Turan, M.E.; Sun, Y.; Ahlatci, H.In this study, the effects of bismuth additions of 0.2, 0.5 and 1 wt% on microstructure and mechanical properties of AZ91 alloy were examined. A permanent mold casting procedure was carried out to produce the alloy billets under a mixed gas atmosphere of SF6 and CO2. Microstructural investigations showed that Mg3Bi2 intermetallic phases were formed in all the samples and it coarsened with increasing amount of Bi in AZ91 alloy. Furthermore, a finer dispersion of Mg17Al12 intermetallic phases was observed in the structures as the amount of Bi in AZ91 increased. It was also showed that increasing Bi addition increased the hardness of AZ91 alloy. However, the highest hardness value was found for the alloy having 0.5wt% Bi addition that means high amount of Bi can decrease the hardness of AZ91 alloy. On the other, there were no considerable changes in the tensile strengths and yield strengths of the alloys as the amount of Bi increased although a slight increase in both strengths were observed with increasing amount of Bi. Percent elongation at break showed a decrease as Bi addition increased.Öğe Effects of titanium addition on mechanical and corrosion behaviours of AZ91 magnesium alloy(Elsevier Science Sa, 2011) Candan, S.; Unal, M.; Koc, E.; Turen, Y.; Candan, E.The mechanical properties and corrosion behaviour of AZ91 magnesium alloy containing 0.2-0.5 wt.% Ti were investigated in this study. Results demonstrate that the enhancement of the ultimate tensile strength by 18% and yield strength by 47% can be achieved by Ti addition. The corrosion behaviour was evaluated by immersion tests and potentiodynamic polarisation measurements in 3.5% NaCl solution. The results from the immersion tests and potentiodynamic polarisation measurements showed that the corrosion resistance of AZ91 alloy increased progressively with the increase of the Ti content of the alloy. Compared to AZ91 alloy, 0.5Ti addition increased the corrosion resistance by up to 45 fold. The mechanism of property enhancement is ascribed to both the suppression of partially divorced beta-Mg17Al12 eutectics and an increased Al content in alpha-Mg solid solution by Ti addition in AZ91 alloy. (C) 2010 Elsevier B.V. All rights reserved.Öğe The Immersion Corrosion Resistance of Shot Peening and MAO Applied on AZ31?0.5% La Sheets(Dr D. Pylarinos, 2020) Elmansouri, G.; Ahlatci, H.; Kara, I.H.; Turen, Y.In this study, the effect of Shot Peening (SP) and Micro Arc Oxidation (MAO) process on the corrosion resistance of 0.5% La with added AZ31 Mg alloy, hot rolled at different rolling speeds, was investigated. It was found that the surface of the rolled material at a rolling speed of 4.7m/min had higher surface smoothness values than the one rolled at 10m/min. It was observed that the corrosion rate changed in the first 40 of 168 hours. In the following hours, the corrosion rate showed different results according to the initial microstructure properties of the base materials. Initially, pore size was the dominant factor determining corrosion resistance, although, after coating, the corrosion rate was affected by the twins formed, based on rolling speed, which enhanced the corrosion rate between 48 and 168 hours. © 2020, Dr D. Pylarinos. All rights reserved.Öğe Improvement of mechanical and corrosion properties of magnesium alloy by lead addition(Elsevier Science Sa, 2009) Candan, S.; Unal, M.; Turkmen, M.; Koc, E.; Turen, Y.; Candan, E.Mechanical properties and corrosion behaviour of AZ91 magnesium alloy containing 0.2-1.0 wt.% Pb were investigated. An enhancement of ultimate tensile strength by 42%, yield strength by 58% and elongation by 20% can be achieved by Pb addition. Corrosion resistance of the AZ91 alloy also increased progressively with increasing Pb content. The mechanism of property enhancement is ascribed to the suppression of intermetallic phases (beta-Mg17Al12 and alpha-Mg+beta eutectic) by Pb addition. (c) 2008 Elsevier B.V. All rights reserved.Öğe INVESTIGATION OF MECHANICAL PROPERTIES OF ACCELERATED COOLED AND SELF-TEMPERED H-TYPE STRUCTURAL SECTIONS(Polska Akad Nauk, Polish Acad Sciences, Inst Metall & Mater Sci Pas, 2023) Isikgul, A.; Ahlatci, H.; Esen, I.; Turen, Y.; Yagiz, O.This study investigates mechanical properties of accelerated cooled and self-tempered (AC-ST) H-type S275JR quality steel sections in HEA120 and HEB120 sizes. The cooling process is conducted with a specially manufactured system that sprays a coolant consisting of a water + compressed air mixture on the section surfaces. Cooling times were applied as 10 and 30 seconds using 4 and 12 bar compressed air + water at an average constant pressure of 5 bar and a constant flow rate of 0.08 kg/s. In the HEA120 sections, the highest cooling rate was obtained with 83 degrees C/s in the web region under the cooling time of 30 s and the air pressure cooling condition of 12 bar. At the cooling rate up to 6 degrees C/s, the microstructure is transformed to acicular ferrite and polygonal ferrite phase from Ferrite+Pearlite. But upper bainite phase was formed at a cooling rate of 30 degrees C/s, and a small amount of martensite and lower bainite microstructures were observed at a cooling rate of 60 degrees C/s and above. The hardness in the untreated sections, in the range of 106-120 HB, was increased to 195 HB at a cooling rate of 83 C/s in the web region of the HEA120 section. For a cooling rate of 23 degrees C/s, the maximum compressive residual stresses of -352 MPa are measured in the crotch region of the HEB120. And for a cooling rate of 6 degrees C/s, the maximum tensile residual stresses of 442 MPa were determined in the flange region of the HEA120 section.Öğe Measurement and prediction of contact angles of Pb-free Sn-Ag solder alloys on Cu substrate(Cambridge Univ Press, 2011) Erer, A. M.; Candan, E.; Guven, M. H.; Turen, Y.The contact angle (Theta) of molten Sn and Sn-Ag alloys (0.5, 1.5, 3.5, 6 wt.% Ag) on Cu substrates have been studied by using sessile drop method at various temperatures (230, 250, 275 and 300 degrees C). Experimental results showed that additions of Ag to Sn resulted in a continuous decrease in the Theta up to 3.5 wt.% above which the Theta value was increased. Increasing alloy temperature also decreased the Theta proportionally. Experimental results revealed that a correlation between the Theta, alloy composition and the alloy temperature exists which yielded an empirical model to predict the Theta at a given Ag content and temperature for a given Sn-Ag alloy. The empirical model predicts the Theta reasonably well with the present work and the other published works.Öğe Mechanical behaviour for aluminum matrix anocomposites reinforced with single and dual nanoparticles (TiO2+ SiO2)(American Institute of Physics, 2024) Mohsin, M.K.; Mustafa, A.M.; Ahlatci, H.; Turen, Y.This paper is devoted to studying the effect of adding different weight ratios of TiO2 and SiO2 nanoparticles powder on the mechanical properties of Al6061. Composite materials containing different proportions of TiO2:SiO2 (0.1, 0.3, 0.5)wt% were poured by the stirring method. The microstructure and phases are achieved through optical microscopy, SEM, and X-ray diffraction. The results showed that a large degree of homogeneity was obtained in the distribution of the addition of nanoparticles in the microstructure of the base alloys. The mechanical properties tests were carried out by tensile and hardness. The final tensile strength and yield strength were increased slightly until reached a maximum value of 151.12 Mpa and yield strength of 74.72 Mpa and show a decrease in elongation to 29.85. The hardness test results showed that the hybrid composite containing 0.5 wt% of TiO2 and SiO2 nanoparticles had a higher hardness of 87.08 compering with the single and dual reinforcement of other nanocomposites and base Al 6061 alloys. © 2024 Author(s).Öğe Microstructure and corrosion properties of homogenized AZ31 and AZ31+1%La magnesium alloys(Trans Tech Publications Ltd, 2017) Ahlatci, H.; Kara, I.H.; Turen, Y.; Sun, Y.; Zengin, H.Energy efficiency and decreasing emission of greenhouse gasses emerge that the importance of Mg alloys. Mg alloys can begin to supersede the steel and aluminum for structural applications, thanks to the developing of mechanical properties or corrosion resistance of these alloys. Rare earth metals such as Gd, Ce, Y and Nd have been utilized at AZ31 Mg alloys for this purpose in recent years. In this study, the effects of La addition and homogenization heat treatment on microstructure, hardness properties and corrosion resistance of AZ31 and modified AZ31 Mg alloys produced by low pressure die casting method were investigated. © 2017 Trans Tech Publications, Switzerland.Öğe Microstructure and corrosion properties of homogenized Mg-4Zn-1La magnesium alloy(Trans Tech Publications Ltd, 2017) Zengin, H.; Turen, Y.; Ahlatci, H.; Sun, Y.; Kara, I.H.In this study, microstructure and corrosion behaviour of homogenized Mg-4Zn-1La magnesium alloy was investigated. Mg-4Zn-1La alloy was produced by low-pressure die casting method. Homogenization treatments were performed at 350 °C and 400 °C for 12, 18, 24 and 48 hours, followed by rapid cooling in water at room temperature. Microstructure characterizations showed that La addition led to a formation of semi-continuous network structure and islands of second phases which identified as T-phase (Mg7Zn3RE). A significant amount of second phase dissolution and an increase in-Mg grain size with increasing both homogenization time and temperature was observed. Homogenization treatment led to an improvement in corrosion resistance of Mg-4Zn-1La alloy. Homogenization at 400 °C resulted in better corrosion resistance than homogenization at 350 °C for all homogenization duration. © 2017 Trans Tech Publications, Switzerland.Öğe Residual stress measurement in rails by destructive and non destructive method(TANGER Ltd., 2015) Turan, M.E.; Ozcelik, S.; Zengin, H.; Ahlatci, H.; Turen, Y.; Tozlu, I.; Sun, Y.Residual stress is an elastic stress in remaining part after the various stages of production. If residual stress values in rails are known, mechanical properties of rails and their effects in railway can be predicted. For this purpose, residual stresses of rails which had same casting number were measured by cutting and X-ray diffraction method in this study. Five rails were used for measurement. Firstly, according to the EN 13674-1 which is railway rails standard, strain gauge that is an electrical apparatus were used and one meter long rails were cut. After cutting, Hooke law was applied and residual stress values of rails were found. The residual stress values were around between 115 MPa and 180 MPa. In addition to standard residual stress measurement, X-ray diffraction method was used to compare between destructive and nondestructive techniques. Five specimens were taken from five rails in the appropriate size for X-ray device. In this method stress values were around between 200 and 400 MPa. After residual stress measurement, Brinell's hardness test was applied to three samples and microstructure of rail which has biggest residual stress value was examined by SEM. The results show that, residual stress values in cutting method were different from X-ray diffraction method and residual stress could affect the rails hardness.Öğe Wear behaviour for aluminum matrix nanocomposites reinforced with (TiO2+SiO2)(American Institute of Physics, 2024) Mohsin, M.K.; Mustafa, A.M.; Ahlatci, H.; Turen, Y.This paper is devoted to studying the effect of adding different weight ratios of TiO2 and SiO2 nanoparticle powder on the corrosion properties and wear resistance of Al6061 alloy. Composite materials contain different proportions of TiO2:SiO2 (0.1, 0.3, 0.5) poured through by stirring. The microstructure and phases are achieved through optical microscopy, SEM and X-ray diffraction. The results showed that a significant degree of homogeneity was obtained in the distribution of the armature particles in the microstructure of the base alloys. The measurement of the wear rate was performed by the pin on the disc device of both the base alloy and the hybrid composite under applied loads (5, 10, and 15 N) and a sliding velocity of 2.8?m/sec using different times (5, 10 and 15?min). The Wear results showed a reduction in the corrosion rate of 0.5 wt% for both TiO2 and SiO2 nanoparticles containing composites compared to other composites and the base alloy samples. And it was worth 0.82*10^-8 gm/cm compared to 1.82*10^-8gm/cm in the base alloy. The hardness test results showed that the hybrid composite containing 0.5 wt% of both TiO2 and SiO2 nanoparticles had higher hardness than other composites and base alloys; the amount of hardness in 0.5%wt hybrid composite became 77.35HV compared to 68.88HV in the base alloy. © 2024 Author(s).
