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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 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 1WT.% Ti, In, and Sn Additions on the Microstructure, Mechanical and Corrosion Properties of the As-Cast and Hot-Rolled AM60 Magnesium Alloys(Springer, 2019) Turen, Y. U.; Zengin, H.; Sun, Ya.; Ahlatci, H.; Unal, M.We study the influence of 1 wt.% Ti, In and Sn additions on the microstructure, mechanical properties and corrosion resistance of the as-cast and hot-rolled AM60 magnesium alloys. The analysis of microstructure was performed by using optical and scanning electron microscopes The phase composition of the alloys and grain sizes are analyzed. We also determine the ultimate strength, yield limit, relative elongation, and corrosion resistance of the alloys. The efficiency of alloying of AM60 alloy with titanium and tin (for the improvement of the mechanical characteristics) and with indium (for the improvement of corrosion resistance) is demonstrated.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 Electrochemical Study of Al2O3/Industrial Waste Coating on Mg Substrate via Sol-Gel Method(Trans Tech Publications Ltd, 2022) Salleh, S.H.; Malek, R.A.; Abdullah, S.S.C.; Zengin, H.; Abidin, A.Z.Industrial waste is primarily handled using landfills in both developed and developing countries. While there has been a significant rise in solid waste reduction, reuse, and recycling, landfill disposal will inevitably remain the most commonly used form of waste management. Although landfilling provides an economic means of waste disposal, it can lead to environmental degradation by releasing various contaminants if not managed properly. In this work, industrial waste from electrostatic precipitators (ESP) will be beneficial for the production of coatings on metal substrates. The sol-gel coating method have been attempted for deposition on pure Mg samples. Using the potentiodynamic polarization (PDP) method and hydrogen evolution analysis, the effectiveness of the coating, which is the corrosion resistance was analyzed. A minimal application of Tetraethyl orthosilicate (TEOS) in the ESP dust solution has been shown to substantially reduce the corrosion rate of Mg. This is likely due to the impact of its concentrations through the sol-gel process that could increase the size of the particle shape or growth. © 2022 Trans Tech Publications Ltd, Switzerland.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.
