SEARCH RESULT

This study includes device design and design for determining the performance of rigid round thin wires under a bending rotating fatig load over a given lifetime. Small diameter wires are thin wires with a diameter equal to or greater than 1.60 mm (0.63 inch). Bending rotating fatig tester ensures that the wire is rotated at constant speed and subjected to constant amplitude bending deformation. For this purpose, the wire retaining pliers are parallel to each other and the wire between the pliers is 180° paralel. After the speed is entered to the driver, the AC motor power is started by means of the belt-pulley and then transferred to the gears with the help of the cardan shaft. The number of cycles is transmitted to the counter by the encoder and recorded. The number of cycles can be generated in response to the bending deformation applied. The test device was reproducible and healthy.

International Iron & Steel Symposium
UDCS

Emre Demirci Hayrettin Ahlatçı Yavuz Sun Yunus Türen Hüseyin Koymatcık

—In the aim of this study; the determination of life in steel materials used in different temperature conditions in thermal power plants has been conducted. In these systems, basic steels with low C levels are use at low temperatures and Cr-Mo added special series steels are use at high temperatures. In cases where the creep resistance is of great importance, the choice of material according to the level of creep resistance comes to the fore. In the industry, non-destructive testing methods have been develop in order to conduct investigations in the actively working systems. There are many volumetric and superficial tests in welded joints. In the non-destructive tests carried out on the material, with replica microstructure copying and mobile measurements come to the fore. In this study, the determination of life of ASTM SA192 quality steel materials, which a reactive at low temperatures, has been studied. Replica microstructure was replicate through a working system and the images were compare according to the first material. Because of this comparison, changes in material microstructure were determined as grain growth. Hardness and thickness values obtained by mobile devices were also exam according to the first material. As a result, 338C temperature and 39 bar internal pressure in the working material, because of 140000 hours, a 17% reduction in thickness and hardness (HB) was seen a decrease of 21%.

International Iron & Steel Symposium
UDCS

Bünyamin ÇİÇEK Yavuz Sun Hayrettin Ahlatçı Yunus Türen

Material conditions are very important in systems operating at high vapor pressure and temperatures. Cr-Mo series special steels used in the thermal power plants of such structures have high creep resistance and long lasting materials. The time from the first production phase to the usage area and subsequent welded joint processes should be carefully monitor. The P91 and P92 series are the highest-grade creep resistance of the steels mentioned in different standards. All stages of these steels should be keep under control. Otherwise, they cannot meet the desired efficiency after welding. In our study, the whole process for the P91 steels from the beginning of the weld to the end is summary as a technical report. For P91 materials, the requirements for pre-welding, welding and post-welding are explain together with the academic data. Many studies on materials P91 have been compile and tried to form a technical guide.

International Iron & Steel Symposium
UDCS

Bünyamin ÇİÇEK Yavuz Sun Hayrettin Ahlatçı Yunus Türen

The aim of this study was to investigate the effect of the material hardness and microstructural characterization of the spring steels having the qualities of 51CrV4, 54SiCr6, 55Cr3 and 60SiCr7 produced according to the heat treatment application conditions. Fragments cut to appropriate sizes from spring steels were subjected to hardening process for 1 hour and tempering temperature for 1.50 hour at austenitization temperature determined from Fe-C balance diagram. When the applied heat treatments were evaluated generally, no differences were observed in the structure of the spring steel as a result of the cooling of the oil and the cooling of the austenitization zone in different cooling environments resulted in differences depending on the internal structure of the mechanical properties. As a result of the cooling process, internal stresses occurred and the microstructure turned into a mantle, resulting in rigidity and brittleness. This martensite structure tempering process reduced the internal stresses of the metallic material, the hardness fell a little and softened.

International Iron & Steel Symposium
UDCS

Esma KESKİN Hayrettin Ahlatçı Yunus Türen Mustafa Ali KÜÇÜK Yasin SUBAŞI

The aim of this study was to investigate the effect of the material hardness and microstructural characterization of the spring steels having the qualities of 51CrV4, 54SiCr6, 55Cr3 and 60SiCr7 produced according to the heat treatment application conditions. Fragments cut to appropriate sizes from spring steels were subjected to hardening process for 1 hour and tempering temperature for 1.50 hour at austenitization temperature determined from Fe-C balance diagram. When the applied heat treatments were evaluated generally, no differences were observed in the structure of the spring steel as a result of the cooling of the oil and the cooling of the austenitization zone in different cooling environments resulted in differences depending on the internal structure of the mechanical properties. As a result of the cooling process, internal stresses occurred and the microstructure turned into a mantle, resulting in rigidity and brittleness. This martensite structure tempering process reduced the internal stresses of the metallic material, the hardness fell a little and softened.

International Iron & Steel Symposium
UDCS

Esma KESKİN Hayrettin Ahlatçı Yunus Türen Mustafa Ali KÜÇÜK Yasin SUBAŞI

In this study; The effect of the heat treatment applied to the samples taken from the domestic production gear part used in the construction machinery, on the heavy abrasive wear is investigated. Samples removed from the threaded part were allowed to stand at 900 ºC for 1 hour and then cooled by quenching. Water samples were tempered at 400 ºC for 1.5 hours. Non-heat-treated and heat-treated samples were subjected to abrasive wear test against 60 mesh Al2o3 sandpaper under 40N, 80N, and 120N load. The abrasive wear resistance of the examined domestic nail in severe abrasive wear conditions improved by 37% in heat treatment

International Iron & Steel Symposium
UDCS

Cemal ÖZGENÇ Hayrettin Ahlatçı Yunus Türen Süleyman Yaşın Esma KESKİN Mustafa Ali KÜÇÜK Yasin SUBAŞI Burcu Çetintaş

Powder metallurgy method is production of parts widely used today. This use is widely used in many areas of the steel materials industry, especially from powder metal parts produced by powder metallurgy method. Since these materials take the form of the final product at the end of production without requiring any machining process. Also, these materials can be used as an iron based bearing material because of the machine parts such as filter, cutting tool bits and they have self-lubricating property due to its porosity. The aim of this study is; stainless steel matrix, boron carbide reinforcement in different ratios (5%, 10%, 15%) is the production of functional graded material. For this reason, stainless steel and boron carbide powders were mixed in V-type mixer for 3 hours. After this process, the samples were produced by means of powder metallurgy under pressure of 45 MPa at 900°C in the hot press machine. The microstructure and boron carbide distribution of the produced samples were examined in the SEM device and hardness measurements were made in order to observe the changes in mechanical properties. When microstructures were examined, it was determined that boron carbides were distributed homogeneously. It was observed that the hardness increased as the rate of support and the transition between the stages increased.

International Iron & Steel Symposium
UDCS

Batuhan Özusta Yasin Akgül Hayrettin Ahlatçı Süleyman Yaşın İsmail Esen Yavuz Sun Yunus Türen

In this study; Rod drew 54SiCr6 and 60SiCr7 steel’s resistance to severe abrasive wear response were examined by the means of comparing Si and Cr contents. The sample pieces with 10 mm diameter and 20 mm high from the medium carbon steels were subjected to abrasive wear test against Al2O3 sandpaper with a particle diameter of 210 µm under 40, 80, 120 N loads. It has been observed that the abrasion resistance of 54SiCr6 and 60SiCr7 medium carbon steels has improved with the decrease of Si content in the structure of steel and the increase of Cr content at the same time.

International Iron & Steel Symposium
UDCS

Esma KESKİN Hayrettin Ahlatçı Yunus Türen Mustafa Ali KÜÇÜK Cemal ÖZGENÇ Yasin SUBAŞI Burcu Çetintaş

In this study; The effect of the solution and aging heat treatments on the corrosion behavior on high chromium cast steel samples with the compositon of 1.61% C + 25% Cr + 0.74% Si + 0.55% Mn + 0.38% Mo + 0,23% Ni + 0.15% V were investigated. The samples solution heat treatment - rapid cooled for 4 hours at 1150 ℃, aged for different times between 5-25 and in cast (original) status were subjected to corrosion treatment. Corrosion behavior was investigated by immersion method in 10% FeCl3 and 10% H2SO4 medium. As a consequence, the least corrosion rate was seen on the sample kept at the solution condition and then cooled by water rapidly while higher corrosion rates were observed on cast (original) status and aged samples.

International Iron & Steel Symposium
UDCS

Mustafa Ali KÜÇÜK Hayrettin Ahlatçı Yunus Türen Soner Arı Yasin SUBAŞI Süleyman Yaşın

—In this study for a teeth wire that has a quality of 316, diameter of 0.4 mm and a tensile strength of 800 MPa, we investigated its fatigue behaviour in two environments: atmosphere and 3,5% NaCl using the methods of simple bending tests. In order to do those tests we decided to use stainless steel braces of model REF500-040-00 and calculated the wire’s length before starting the test using the following law: (L = (c * 2.17) +31). The tests have been done according to the room temperature and frequency of 10 Hz. We used the lean bias device to perform the test which requires the fully reversible stress (R=min/ max= −1). After that we examined the fractured surfaces of fractured samples that were close to the deformation limit of fatigue using SEM in order to know their fracture mechanism. We have observed that the corrosive environment caused the fatigue to result in a different mechanism.

International Iron & Steel Symposium
UDCS

Rahma Shaaban Tuğba Akçabaş Hayrettin Ahlatçı Yunus Türen Yavuz Sun Yasin SUBAŞI Ömer Onat Hüseyin Koymatcık

In this study, fatigue behavior of 55Cr3 metal alloy spring steel which is produced as hot and cold was examined. Fatigue samples with a diameter of 10 mm, extracted from 55Cr3 spring steel in accordance with ISO 1143 standard, were subjected to rotational bending fatigue testing of different masses under repeated bending stresses according to a continuous rotating neutral axis. As a result of the investigations, the fatigue strength of 55Cr3 spring steel decreased with hot process, while the cold process increased.

International Iron & Steel Symposium
UDCS

Esma KESKİN Hayrettin Ahlatçı Yunus Türen Hüseyin Zengin Mustafa Ali KÜÇÜK Yasin SUBAŞI

Heat treatment methods are the most commonly used production steps because they can interfere with all the mechanical properties of the material without altering the chemical composition of the metal in industry. Accelerated cooling is also one of the most prominent points in the series production process in these heat treatment methods. This method is used in the manufacturing process of thin pearlitic steel, double phase steel, rayon sheet steel which is used for bainitic steel production, from construction bar to profile in many different quality and size products. In this study, S355J2 corrugated corrugations and S275JR quality HEA-HEB structural section steels were produced from hot rolled billets produced by open casting method. Intensive inclusions were found in both of the materials examined and it was seen that they could not meet the mechanical strength values in the sizes with low crushing rates. These materials, especially those with low impact strength, have been subjected to accelerated cooling to increase their impact strength.

International Iron & Steel Symposium
UDCS

Fatma KÖZ Furkan ACAR Emre Demirci Hayrettin Ahlatçı Yavuz Sun Yunus Türen Mustafa DEMİRKAZIK Mesut KAYMAZ Şerafettin ÖNER

In this work, the wear resistance behavior of GG-25 gray cast iron was investigated. Three specimens with different austempering time (120, 90 and 60 minutes) and one specimen, which is not austempering, were used. With this manner it has been tried to examine the effect of the parameters of austempering process on each specimen. Pin-on-disc wear resistance test with one loads (20N) on every specimens has been applied according to of ASTM 99 standards. SEM to observe the microstructures characterized the austempered specimens. In addition, brinnel hardness test was applied. With the results of the wear resistance test, as the austempering time increased, wear resistance also increases.

International Iron & Steel Symposium
UDCS

Abdulsamet YILDIRIM Yunus Türen Hayrettin AHLATCI Yavuz Sun Mustafa GUÇLU Hamza Serhat AYDEMIR Mehmet Sami TAKVA

In this study, the effect of C addition on the corrosion behavior of wire rods of 5.5 mm in diameter was investigated. The horizontal and vertical cross sections of the wire rods with 0.7, 0.8, 0.9 C ratio were taken during the metallographical process. The microstructure of the examined specimens was examined by light optical (LOM) and scanning electron microscopy (SEM). Hardness test of steel containing 0.7- 0.9 C was carried out in shimadzu brand micro hardness tester. Corrosion tests of the prepared samples were evaluated according to both the weight loss and the Potentiodynamic Polarization measurements in 3.5% NaCl solution. Despite the increased hardness of the specimens examined, the corrosion resistance decreased. This can be caused by inclusions in the microstructure.

International Iron & Steel Symposium
UDCS

Medine Kilinc Gulheser Dogancik Yunus Türen Yavuz Sun Hayrettin AHLATCI İbrahim AFŞAR Serhat ÖZDEMİR Hüseyin Koymatcık Hüseyin Zengin

In this study, the effect of carbon content in the range of 0,7-0,9 on wear resistance was investigated. The examined specimens in 5.5 mm diameter are manufactured with drawing process. Wear tests of the cylindrical samples with a length of 20 mm were examined in pin-on-disc type wear tester on counter face of 1.2379 cold work tool steel under the load of 30-60 N. The weight losses of the samples examined increase with the increase of carbon content and hardness. Wear Mechanism is mild wear to oxidative wear.

International Iron & Steel Symposium
UDCS

Semih Gezer Hayrettin Ahlatçı Çağatay Aslan Yunus Türen Yavuz Sun Melike Birinci Meryem Yıldız Neşe ÇAĞLAYAN Hüseyin Koymatcık

- In this study, Cr-W steels were produced by casting then heat treatment was applied for specimens. After the normalization process at 1100 0C for 1 hour, samples were heated up 660 0C and 760 0C to evaluate the effect of tempering temperature. One group of steel were waited at 1 hour and the other group were waited at 2 hours in these temperatures. Hardness of specimens was measured according to the Vickers test method. Wear tests were performed for all specimens under the loads of 10N, 20N and 40N in dry sliding conditions. Microstructure analysis was carried out using Light Optical Microscope (LOM), Scanning Electron Microscope (SEM). Results show that, tempering temperature significantly affects the wear behaviors of samples. These effects can be seen especially under higher loads. And also there is a direct proportion between wear and hardness results

International Iron & Steel Symposium
UDCS

Fatih AYDIN Yavuz Sun MUHAMMET EMRE TURAN Mustafa ACARER Hayrettin Ahlatçı Yunus Türen

In this study, influence of grain size on degree of sensitization and susceptibility to intergranular corrosion of AISI 316 austenitic stainless steel was investigated. As-received AISI 316 austenitic stainless steel samples were first solution heat treated at 1050 oC for 0.5 h, 1.5 h and 3 h in order to obtain different grain sizes and then, each of them was heat treated for sensitization at 700 oC for 1h followed by water quenching. Grain size measurements of the first set of samples were performed by linear intercept method according to ASTM E112 standard and the degree of sensitization was measured by double loop electrochemical potentiodynamic reactivation (DLEPR) test. The results showed that grain size increased as the solution heat treatment time increased. A decrease in the degree of sensitization was observed for the samples having larger grains. That is to say, the increase in grain size improved intergranular corrosion resistance.

International Iron & Steel Symposium
UDCS

Hüseyin Zengin Yunus Türen Hayrettin Ahlatçı Yavuz Sun Burak Dursun Ünsever

In this work we measure and estimate, experimentally and numerically, approximate fatigue strengths of steel filaments of 0.25 mm diameter with 80% C by the pure bending test method. All fatigue tests have been realized at room temperature and at a frequency of 10 Hz via a custom manufactured pure bending tester of which the fully reserved strain value, R = εmin/εmax, is −1. The applied value of cyclic deformation, ε, has been chosen from the range 0.46-1.07. The plots of S-N (Strain–Cycle) curves are based on high fatigue cycle (HFC) lives that are greater than or equal to 106 cycles.

International Iron & Steel Symposium
UDCS

Hüseyin Koymatcık Hayrettin Ahlatçı Yunus Türen Yavuz Sun SAİT ÖZÇELİK

The aim of this study is to investigate the effect of nitration and nitrox process on wear performances of tool steels. For this purpose, samples were seperated as two categories. One group was exposed to nitration process in salt bath at 530 0C during 6 hours. For other group, nitrox process was applied at 4900C during 2 hours after nitration. Reciprocating wear test was performed for all specimens under the loads of 10N, 20N and 40N according to the ASTM G99 standard. Microstructures and worn surfaces of specimens were analysed using Scanning Electron Microscope (SEM). Results show that, wear performances of specimens exhibit difference when they are exposed nitration and oxidation process. And also they show better performance under the lower loads.

International Iron & Steel Symposium
UDCS

M. Emre TURAN Mustafa ACARER M.Karakus Hayrettin Ahlatçı Yunus Türen Yavuz Sun

Bu çalışmada, patlamalı kaynak tekniği ile üretilmiş alüminyum-çelik-alüminyum tabakalı kompozit numunelerin, plaka yorulma cihazı ile, yorulma davranışı incelenmiştir. Kompozit imalatında, 0.5 mm kalınlığında 1110 kalite çelik ve 1.5 mm kalınlığında 1050 kalite alüminyum saclar kullanılmıştır. Tabakalı kompozitlerle imal edilen plaka parçalar dinamik yüklemelere maruz kaldığı için yorulma davranışının bilinmesi önem arz etmektedir. Tabakalı kompozitler özellikle plaka halde kullanıldığından Şekil 1’de görülen plaka yorulma test numunesi Şekil 2’de verilen plaka yorulma test cihazı ile incelenmiştir.

International Symposium on Light Alloys and Composite Materials
UHAKS

Sakine Obuz Gülcan Çetin Fikri Günsur İlayda Şahin Furkan ACAR Sait Özçelik Mustafa ACARER Süleyman Yaşın Yunus Türen Yavuz Sun Hayrettin Ahlatçı

Bu çalışmada; %0,5 Sn ve %0,5 Pb ilaveli AM60 magnezyum alaşımının mikroyapı ve mekanik özellikleri, optik mikroskop ve çekme testi cihazı kullanılarak incelendi. Döküm işlemi Şekil 1’ deki dört kademeden oluşan 300 °C ye ısıtılmış kademeli kalıp içerisinde yapıldı. Alaşım elementleri hassas terazide tartılarak ayarlandı. Tablo 1’ de alaşımların kimyasal analizleri görülmektedir. Metalografik incelemeleri yapılmak üzere numunelerin yüzeyleri sırası ile 320, 400, 600 ve 800 mesh zımparalar ile saf su kullanılarak zımparalama ve 1μm alümina pasta kullanılarak polisaj keçesinde parlatma işlemine tabi tutuldu ve %75 etilen glikol, %24 saf su, %1 HNO3 karışımı ile dağlandı. Çekme deneyleri için numuneler ASTM E 8M-99 standardına göre hazırlandı. Çekme deneyi uygulaması için ise 5 ton çekme kapasitesine ayarlanabilen çekme cihazında ve 0,5 mm/dk çekme hızında yapıldı. Sertlik deneyi numuneleri çekme çubuğundan 8x5 boyutlarında çıkartıldı ve yüzeyleri zımparalanarak parlatıldı. 1 mm çaplı elmas kare piramit uç ve 50 N yük uygulanarak Vickers cinsinden sertlik değerleri elde edildi.

International Symposium on Light Alloys and Composite Materials
UHAKS

Levent Elen Mehmet Ünal Özcan Büyükgenç Bünyamin ÇİÇEK Ferdi Yıldırım Yavuz Sun Yunus Türen Hayrettin Ahlatçı Erkan Koç

Bu çalışmada; %0,5 Sn ve %0,5 Pb ilaveli AM60 magnezyum alaşımının mikroyapı ve mekanik özellikleri, optik mikroskop ve çekme testi cihazı kullanılarak incelendi. Döküm işlemi Şekil 1’ deki dört kademeden oluşan 300 °C ye ısıtılmış kademeli kalıp içerisinde yapıldı. Alaşım elementleri hassas terazide tartılarak ayarlandı. Tablo 1’ de alaşımların kimyasal analizleri görülmektedir. Metalografik incelemeleri yapılmak üzere numunelerin yüzeyleri sırası ile 320, 400, 600 ve 800 mesh zımparalar ile saf su kullanılarak zımparalama ve 1μm alümina pasta kullanılarak polisaj keçesinde parlatma işlemine tabi tutuldu ve %75 etilen glikol, %24 saf su, %1 HNO3 karışımı ile dağlandı. Çekme deneyleri için numuneler ASTM E 8M-99 standardına göre hazırlandı. Çekme deneyi uygulaması için ise 5 ton çekme kapasitesine ayarlanabilen çekme cihazında ve 0,5 mm/dk çekme hızında yapıldı. Sertlik deneyi numuneleri çekme çubuğundan 8x5 boyutlarında çıkartıldı ve yüzeyleri zımparalanarak parlatıldı. 1 mm çaplı elmas kare piramit uç ve 50 N yük uygulanarak Vickers cinsinden sertlik değerleri elde edildi.

International Symposium on Light Alloys and Composite Materials
UHAKS

Levent Elen Mehmet Ünal Özcan Büyükgenç Bünyamin ÇİÇEK Ferdi Yıldırım Yavuz Sun Yunus Türen Hayrettin Ahlatçı Erkan Koç

Bu çalışmada; %0,5 Sr ve %0,5 TiB ilave edilen magnezyum alaşımının mikroyapı ve mekanik özellikleri, optik mikroskop ve çekme testi cihazı kullanılarak incelendi. Döküm işlemi Şekil 1’ deki dört kademeden oluşan 300 °C ye ısıtılmış kademeli kalıp içerisinde yapıldı. Alaşım elementleri hassas terazide tartılarak ayarlandı. Tablo 1’ de alaşımların kimyasal analizleri görülmektedir. Metalografik incelemeleri yapılmak üzere numunelerin yüzeyleri sırası ile 320, 400, 600 ve 800 mesh zımparalar ile saf su kullanılarak zımparalama ve 1μm alümina pasta kullanılarak polisaj keçesinde parlatma işlemine tabi tutuldu ve %75 etilen glikol, %24 saf su, %1 HNO3 karışımı ile dağlandı. Çekme deneyleri için numuneler ASTM E 8M-99 standardına göre hazırlandı. Çekme deneyi uygulaması için ise 5 ton çekme kapasitesine ayarlanabilen çekme cihazında ve 0,5 mm/dk çekme hızında yapıldı. Sertlik deneyi numuneleri çekme çubuğundan 8x5 boyutlarında çıkartıldı ve yüzeyleri zımparalanarak parlatıldı. 1 mm çaplı elmas kare piramit uç ve 50 N yük uygulanarak Vickers cinsinden sertlik değerleri elde edildi.

International Symposium on Light Alloys and Composite Materials
UHAKS

Levent Elen Yunus Türen Melek YILKI Bünyamin ÇİÇEK Ferdi Yıldırım Yavuz Sun Hayrettin Ahlatçı Mehmet Ünal Erkan Koç

Bu çalışmada; %0,2 ve %1 oranlarında Sb ilave edilen AZ91 magnezyum alaşımının mikroyapı ve mekanik özellikleri, optik mikroskop ve çekme testi cihazı kullanılarak incelendi. Döküm işlemi Şekil 1’ deki dört kademeden oluşan 300 °C ye ısıtılmış kademeli kalıp içerisinde yapıldı. Alaşım elementleri hassas terazide tartılarak ayarlandı. Tablo 1’ de alaşımların kimyasal analizleri görülmektedir. Metalografik incelemeleri yapılmak üzere numunelerin yüzeyleri sırası ile 320, 400, 600 ve 800 mesh zımparalar ile saf su kullanılarak zımparalama ve 1μm alümina pasta kullanılarak polisaj keçesinde parlatma işlemine tabi tutuldu ve %75 etilen glikol, %24 saf su, %1 HNO3 karışımı ile dağlandı. Çekme deneyleri için numuneler ASTM E 8M-99 standardına göre hazırlandı. Çekme deneyi uygulaması için ise 5 ton çekme kapasitesine ayarlanabilen çekme cihazında ve 0,5 mm/dk çekme hızında yapıldı. Sertlik deneyi numuneleri çekme çubuğundan 8x5 boyutlarında çıkartıldı ve yüzeyleri zımparalanarak parlatıldı. 1 mm çaplı elmas kare piramit uç ve 50 N yük uygulanarak Vickers cinsinden sertlik değerleri elde edildi.

International Symposium on Light Alloys and Composite Materials
UHAKS

Levent Elen Yunus Türen Bünyamin ÇİÇEK Yavuz Sun Ferdi Yıldırım Hayrettin Ahlatçı Mehmet Ünal Erkan Koç

Abstract Fiber Metal Laminate (FML) with specific strength and low densities, which is a family of hybrid composite structure formed from the combination of metal layers sandwiching a fiber-reinforced plastic layer, have big potential in aeronautical applications in nowadays [1]. Researchers have tried to fabricate laminated composite materials in order to meet demands of industry. Available literature describes already applied laminates consisting of aluminium alloys and glass fibres (GLARE®), carbon fibres (CARALL®) and aramid fibres (ARALL®) [2]–[4]. Today, materials research is moving towards natural fibre composites/laminates. It is because of factors such as low weight, cost effectiveness, man’s desire to go in for natural products, environment friendliness, renewable nature, biodegradability with respect to fiber, and ready use of plants/trees with less processing [5]. The aim of this study is to investigate of microstructural and mechanical performance of metal laminated composite using both natural fibers and industrial fibers as reinforcement. 1050 H24 Aluminum sheet with 0.25 mm thickness was used as matrix material. Silk fabric and S2-glass fiber were reinforced with aluminum separately. Aluminum sheets were cut to suitable size for hot pressing. Mechanical grinding was applied to improve surface roughness and adhesion mechanism. Metal sheets were washed with distilled water and ethanol, respectively. Then they were waited in the chromic acid solution. Epoxy resin and hardener were weighed (100:20 ratio %wt) and mixed homogenously for lamination process. Two different samples for each reinforced composite were prepared for curing process under heat and pressure in the hot-pressing device according to the metal-fiber-metal- fiber-metal stacking sequence (Figure 1) by hand lay-up. The prepared laminate composites were cured at 80 °C and under 1 ton pressure for three hours. Microstructures of laminate composites were characterized using Scanning Electron Microscope (SEM). Samples were prepared for tensile test to examine mechanical properties. Results show that good adhesive bonding was achieved and there were no macro defects such as porosities in microstructure for all specimens. Composites exhibited different mechanical performance (Table 1) and S-2 glass fiber reinforced composite showed best mechanical properties among the specimens. But when the adhesion mechanism of the silk fabric to the resin is improved, it can be used as an alternative natural reinforcement for fiber metal laminates.

International Symposium on Light Alloys and Composite Materials
UHAKS

Mustafa Yunus ASKIN Yunus Türen MUHAMMET EMRE TURAN Yavuz Sun Hayrettin Ahlatçı

Zinc (Zn) has been widely used as main alloying element in magnesium alloys. Zn improves corrosion resistance and strength of magnesium alloys by grain boundary strengthening, solid solution and precipitation hardenings [1,2]. Zn has 6.2 wt% maximum solid solubility in Mg and together with Mg can form binary coherent compounds [3].

International Symposium on Light Alloys and Composite Materials
UHAKS

Hüseyin Zengin Yunus Türen Hayrettin Ahlatçı Yavuz Sun Emre Öztürk

In the study, the AZ31 and AZ31+ La%0.2 Mg alloys were produced by low pressure casting method following homogenization at 400°C for 24 hours and the hot rolling process applied with 15% deformation rate per pass at 400°C. The surface treatment process of shot peening was practised on materials for enhancement corrosion properties of them. To observe corrosion behaviour of investigated alloys the immersion corrosion test in %3.5 NaCl environment and metallographic examination were utilized.

International Symposium on Light Alloys and Composite Materials
UHAKS

Soner Arı İsmail Hakkı Kara Medine Kılıç Yaren Karauğuz Okan Ünal Yunus Türen Yavuz Sun Süleyman Yaşın Batuhan Özusta Hayrettin Ahlatçı

In the study, the AZ31 and AZ31+ La%0.5 Mg alloys were produced by low pressure casting method following homogenization at 400°C for 24 hours and the hot rolling process applied with 15% deformation rate per pass at 400°C. The surface treatment process of shot peening was practised on materials for enhancement mechanical properties of them. The surface roughness of AZ31 and AZ31+ La%0.5 Mg alloys how is developed by shot peening process also was determined.

International Symposium on Light Alloys and Composite Materials
UHAKS

Nihal Kanca İsmail Hakkı Kara Özlem Keleş Canan Dursun Okan Ünal Yunus Türen Yavuz Sun Hayrettin Ahlatçı Süleyman Yaşın

This work investigates the effect of Bi addition, 1 wt.%Bi, on wettability of the Sn–3Ag–0.5Cu (SAC305) ternary pb-free solder alloy. Adding Bi to SAC305 decreased the contact angles (θ) of the Sn-2Ag-0.5Cu-1Bi quaternary pb-free solder alloy decreased which were measured by using of the sessile drop method at various temperatures (250, 280 and 310 °C) on Cu substrate in Ar atmosphere [1]. Microstructures, inter-metallic phases, and melting temperatures of alloys were characterized by optic microscope and scanning electron microscope and energy dispersive X-ray spectroscopy, X-ray diffraction, and differential scanning calorimeter, and effects of the amount of In on microstructure were investigated. The results showed that when the addition of Bi was 1 wt.%, the change in melting temperature of Sn–2Ag-0.5Cu–1Bi solder was negligible, but the contact angles (θ) of the solder alloy decreased which were measured by using of the sessile drop method at various temperatures (250, 280 and 310 °C) on Cu substrate in Ar atmosphere [1]. The lowest θ was obtained as 35,59°for Sn–2Ag-0.5Cu–1Bi alloy at 310 °C. The formation of intermetallic compounds (IMC) between the Pb-free solder alloys and the Cu substrate was observed. As a result, the studies show that the wetting capability of Sn–2Ag-0.5Cu–1B alloy is better than Sn–3Ag-0.5Cu alloy.

International Symposium on Light Alloys and Composite Materials
UHAKS

Serkan Oguz Ahmet Mustafa Erer Yunus Türen

Abstract In this study, AZ31 and AZ31+1.0La wt% alloys were produced by a low pressure die casting method. The rolling capability of these alloys was investigated at different rolling parameters such as speeds and deformation rates. Macro images of sheets were utilized to observe effects of amount La on rolling capability and light optical microscopy, were employed to characterize the microstructure of the alloys. It was observed that crack formation usually was occurred on lower rolling speeds and higher deformation rates.

International Symposium on Light Alloys and Composite Materials
UHAKS

İsmail Hakkı Kara Hayrettin Ahlatçı Yunus Türen Yavuz Sun Mehmet Ünal

Magnezyum otomotiv, havacılık, ilaç, spor ve taşınabilir mikroelektronik sistemler gibi endüstrilerde yaygın olarak kullanılan düşük yoğunluk ve yüksek dayanım özelliği gösterebilen, alaşımlandırılabilir bir malzeme olarak yaygın olarak kullanılmaktadır [1,2]. Bu çalışmada Magnezyum (Mg) malzemeye üç farklı oranda Kalay (Sn) ilavesinin (%3, %6, %9), Magnezyum malzemenin işlenebilirliğinde yüzey pürüzlülüğüne etkisi araştırılmıştır. Magnezyum malzemeye kalay ilavesi yapılarak 50 mm çapında Mg-Sn alaşımı çubuk malzeme üretilmiştir. Bu malzemeler, PID (Proportional Integral Derivative) denetim yöntemi ile motor kontrolü yapılan CNC tabanlı bir tezgâhta işleme deneylerine tabi tutulmuştur. Deneyler sonucunda PID sistemde işlenen iş parçalarının yüzey pürüzlülükleri ölçülmüştür ve performans açısından karşılaştırılmıştır. Deneylerde kullanılan işleme parametreleri Tablo 1’de verilmiştir. Kesme işleminde TCGT 16T308-270 kesici takım ve uygun takım tutucu kullanılarak işlem gerçekleştirilmiştir (Şekil 1)

International Symposium on Light Alloys and Composite Materials
UHAKS

Metin ZEYVELİ Yunus Türen Abdulrezzak ERDEM Süleyman Yaşın

Magnesium have an enormous potential for automobile and aerospace industries due to its low density, high specific strength and good damping ability [1]. However, the low wear resistance and low mechanical properties of Mg hinder the use of Mg in industrial applications [2]. To improve these low properties of Mg, Mg metal matrix composites are widely produced with different reinforcements such as SiC [3], B4C [4], Al2O3 [5]. TiC is a reinforcement material with high hardness and extreme wear resistance [6]. However, the investigation of the effect of TiC on mechanical and wear properties is quite limited.

International Symposium on Light Alloys and Composite Materials
UHAKS

Fatih AYDIN Yavuz Sun MUHAMMET EMRE TURAN Hayrettin Ahlatçı Yunus Türen Mustafa ACARER

Magnesium alloys have great potential in aerospace, automotive and electronic industries due to high specific strength and low densities [1], [2]. Because high specific strength and lightweight materials are needed to improve energy efficiency [3],[4]. However, magnesium alloys have poor mechanical properties, so this situation limits the usage of magnesium in practical applications. There have been a lot of attempts by researchers to overcome deficiencies of magnesium alloys, especially for decades. Researchers develop mechanical properties of magnesium by incorporating reinforcement materials. Micron size reinforcements are generally preferred but nowadays, nano-size materials especially carbon based are becoming popular subject for researchers. In this study, graphene nanoplatelets (GNPs) which is an allotrope of carbon is used as a reinforcement material for magnesium matrix composite. Aluminum was also used to evaluate its binding effects on Mg-GNPs composite. Pure Mg, Mg-0.25 wt.% GNPs, Mg-3Al-0.25 wt.% GNPs and Mg- 9Al-0.25 wt.% GNPs composites were fabricated using semi powder metallurgy technique. GNPs was exposed to ultrasonication process in ethanol for an hour in order to break Vander Waals bonding between carbon atoms. Mg-Al powder (mixed in Turbula mixer for two hours) was added to GNPs/Ethanol solution. Powders were mixed using magnetic stirrer which is connected to the vacuum distillation system. Process was continued until the ethanol removed from the system. Then obtained powder was dried in vacuum drying oven. Dried powders were compacted in graphite mold under 50 MPa applied load in hot pressing device. Argon was used to prevent oxidation and pressing, and sintering temperatures were chosen as 550 ºC. Experimental densities were calculated by Archimedes technique. Microstructures of produced samples were characterized using X-ray diffraction and Scanning Electron Microscope (SEM). Hardness test was applied according to the Vickers test method. Compression tests were performed for all samples to investigate mechanical effects of aluminum and GNPs on magnesium-based composite. Results show that uniform distribution of carbon atoms is seen for GNPs reinforced composites. Figure 1 shows SEM images of Mg-3Al-GNPs and Mg-9Al-GNPs composites. Microstructures are free of macro porosities. As shown in Table 1, hardness of pure magnesium is significantly improved with the addition of Aluminum and GNPs. It can be concluded that reinforcement materials may restrict the dislocation motion and aluminum can exhibit lubricant effect between matrix and GNPs. Compression tests reveal that 0.2% Compression Yield Strength (CYS) and Ultimate Compression Strength (UCS) are enhanced with the addition of reinforcement. Thus, mechanical properties of pure magnesium were significantly improved even low content of carbonaceous reinforcement.

International Symposium on Light Alloys and Composite Materials
UHAKS

MUHAMMET EMRE TURAN Yavuz Sun Fatih AYDIN Hüseyin Zengin Yunus Türen Hayrettin Ahlatçı

Abstract Rare earth (RE) additions can improve mechanical properties at room and elevated temperatures, formability and castability of magnesium alloys [1-3]. Recently, numerous studies have been conducted about wrought Mg-Zn-Zr- RE alloys due to their excellent strength and great potential for further development. In this study, microstructure, mechanical and corrosion properties of as-cast and as-extruded Mg-6Zn-0.5Zr (wt%) alloy, also denoted as ZK60, with minor La addition were investigated. Mg-6Zn-0.5Zr-0.2La magnesium alloy was produced by low-pressure die casting method under a protective argon gas atmosphere. Pure Mg (99.9%) ingots were melted at 750 °C and pure Zn (99.7%), Mg-30 wt% Zr and Mg- 30 wt% La master alloys were added into the molten Mg. The melt was held at this temperature for 30 min and stirred for 15 min to ensure a full dissolution of alloying elements. After applying a pressure of 2 bar into the air tight electric resistance furnace, the melt was transferred from the crucible to the steel mould preheated to 250 °C through the rising steel tube and cylindrical ingots with a diameter of 34 mm and length of 190 mm were obtained. After casting, the as-cast alloys were homogenized at 400 °C for 24 h and water quenched. Then, each homogenized billet was machined into cylindrical bar with a diameter of 32 mm and length of 30 mm. For extrusion process, the machined billets and the extrusion die were preheated to the target temperature for 40 min and directly extruded at an initial temperature of 300 °C with an extrusion ratio of 16:1 and a ram speed of 0.3 mm.s-1. Microstructure characterizations were conducted by a Nikon optical microscope (OM) and a Carl Zeiss Ultra Plus field emission scanning electron microscope (SEM) equipped with an energy dispersive spectroscopy (EDS). The constituent phases in the as-cast alloy and the macro-texture of the extruded alloy were characterized by X-ray diffraction (XRD-Rigaku Ultima IV). Tensile tests were conducted on a Zwick/Roell Z600 universal testing machine at a strain rate of 1.67 x 10-3 s-1 at room temperature (RT). The samples for immersion corrosion test (Φ 5 mm x 15 mm) were cut from the half radius of the alloys, followed by grinding and polishing. Then, the samples were immersed in 3.5 wt% NaCl solution at room temperature for 72 h. The electrochemical corrosion tests of the alloys were also performed in 3.5 wt% NaCl solution at room temperature by a Gamry model PC4/300 mA potentiostat/galvanostat with DC105 corrosion analysis.

International Symposium on Light Alloys and Composite Materials
UHAKS

Hüseyin Zengin Yunus Türen MUHAMMET EMRE TURAN Hayrettin Ahlatçı Yavuz Sun

Bu çalışma kapsamında 1075 ve 15N20 kalite çeliklerinden patern kaynağı yöntemiyle imal edilmiş olan damascus çeliğinin mikroyapı analizleri, vickers sertlik değerleri, darbe-çentik enerjisi değerleri ve standartlarca hazırlanan numunelerle(Şekil.1) yapılan yorulma deneyinden elde edilen sonsuz yorulma ömrü ve wöhler eğrisi belirlenmiştir. İncelenen damascus çeliği korozyon dayanımları ve mekanik özellikleri birbirinden farklı olan 1075 ve 15N20 kalite çeliklerinden patern kaynağı yöntemiyle imal edildiğinden dolayı tabakalı çelik-çelik kompozit bir yapıya sahiptir.[1-8] Yüksek mukavemetli çeliklerin alternatifi düşünülebilecek damascus çeliğinin hareli(tabakalı) yapısının dinamik yükler karşısında sergileyeceği yorulma davranışının belirlenmesi amacıyla plaka yorulma deneyi şuana kadar başka bir çalışmada yapılmamıştır.

International Symposium on Light Alloys and Composite Materials
UHAKS

Furkan ACAR Fatma KÖZ Hakan KIRDAN SAİT ÖZÇELİK Yavuz Sun Yunus Türen Süleyman Yaşın Emre Demirci Hayrettin Ahlatçı

This study reports the investigation on indium addition into Sn–3Ag-0.5Cu ternary lead-free solder to improve its various performances. The effects of indium addition on wettability of the solder alloy was studied. The results showed that when the addition of indium was 1 wt.%, the change in melting temperature of Sn–2Ag-0.5Cu–1In solder was negligible, but the contact angles (θ) of the solder alloy decreased which were measured by using of the sessile drop method at various temperatures (250, 280 and 310 °C) on Cu substrate in Ar atmosphere [1]. Microstructures, inter-metallic phases, and melting temperatures of alloys were characterized by optic microscope and scanning electron microscope and energy dispersive X-ray spectroscopy, X-ray diffraction, and differential scanning calorimeter, and effects of the amount of In on microstructure were investigated. The lowest θ was obtained as 35,55°for Sn–2Ag-0.5Cu–1In alloy at 310 °C.

International Symposium on Light Alloys and Composite Materials
UHAKS

Okan Uyanık Ahmet Mustafa Erer Yunus Türen

In this work, Brinell hardness test, impact test, bend test results of four different types of honeycomb composite materials, which are important for todays in the Civil Aviation Sector and which have been undergoing significant improvements over the past 20 years, have been investigated. The thickness of the mechanical properties of the composites differed with the length of the part and the chemical resin used. The white material in 1,2 cm thickness is used in side and ceiling in cargo area. The light yellow materials is 1,2 cm thickness and is used on the cargo floor and on the wet and dry floors of Airbus, Boeing branded aircraft. Black materials (on wet floors) material in 9,9 cm thickness and used in Passenger Glasses. Yellow Color resinized honeycomb composite in lyophilized form is 1cm thick and used on the bottom of cargo section. Hardness measurements were carried out with a 2.5 mm ball and a load of 187.5 kg under the Brinell Hardness Tester . When the hardness results were examined, when the white composite was damaged, the highest hardness value was found as yellow composite (54,92 HB) value of black composite (26.02 HB). The open saddle stiffness is 31,43 HB.

International Conference of Advanced Materials and Manufacturing Technologies
ICAMT

Muharrem Ilbeyi Incedere Emre Yildirim Emre Demirci Batuhan Ozusta Hayrettin AHLATCI Yavuz Sun Yunus Türen SAİT ÖZÇELİK Fazil Hüsem

In this study, the effect of homogenization heat treatment on the corrosion behaviour and mechanical properties of Co-Cr (Dental), Co-Cr (Denture) and Ni-Cr (Dental) based casting materials used as dental implant materials was investigated. Samples prepared as 7 mm in diameter x 10 mm cylindrical in a special silicon-graphite-containing powder mixture for preventing oxidation were annealed at different times in the range from 0.5 to 3 hours at 1000 ° C. Microstructural investigations of the samples heat treated and casted was performed on longitudinal and circular sections by Leica DM ILM model optical light microscope and then hardness measurements were carried out with Brinell hardness tester with 2,5 mm ball and 187,5 kg load. The corrosion behaviour of the Co-Cr and Ni-Cr based materials formed in the optimum parameters, which show improvement in the final mechanical properties of microstructure and hardness measurement data, compared with cast materials, was studied by potentiodynamic polarization test in Hanks liquid. The corrosion damage mechanism was determined by scanning electron microscopy. The icorr and Ecorr values of the heat-treated materials evaluated after the corrosion made by the potentiodynamic polarization test method has been increased with respect to that of the casted materials.

International Conference of Advanced Materials and Manufacturing Technologies
ICAMT

Medine Kilinc Batuhan Ozusta Gulheser Dogancik Canan Dursun Hayrettin AHLATCI Yunus Türen Yavuz Sun Alperen R.B. ÖZSARI

In this study, the wear behavior of hot rolled AZ31 and AZ31-X wt% La Mg alloys were investigated. After the microstructure characterization, hardness and wear tests, the effect of La on the wear resistance of AZ31 Mg alloy were reported. Hot Rolling process introduced the twins and DRXs on the microstucture wherein the changing of grain boundaries density impart wear resistance to AZ31 Mg alloy.

International Conference of Advanced Materials and Manufacturing Technologies
ICAMT

İsmail Hakkı Kara Hayrettin Ahlatçı Yunus Türen Yavuz Sun Harun ÇUĞ Mehmet Ünal