Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Çolak, Murat(4)
- Dispinar, Derya(2)
- Aldemir, Alper(1)
- Alemdag, Y.(1)
- Alnahhal, A. M.(1)
- Ammas, G.(1)
- Anil, Özgür(1)
- Ayata, Ümit(1)
- Ayough, P.(1)
- Bardakci, S.(1)
- Büşra Avlayan(1)
- Can, Ömer(1)
- Ciza, Baraka(1)
- Colak, Murat(1)
- Demirtas, M.(1)
- Dobatkin, S.V.(1)
- Erbayrak, Engin(1)
- Gerdan, Zeynep(1)
- Gumus, Beril Eker(1)
- Gursoy, Ozen(1)
- Gökçe, H. S.(1)
- Gökçe, H. Süleyman(1)
- Gökçe, H.S.(1)
- Kahraman, Yusuf(1)
- Kutsal, U.(1)
- Nehdi, M. L.(1)
- Purcek, G.(1)
- Sarper, G.(1)
- Sağnak, Y.(1)
- Shangina, D.V.(1)
- Simsek, O.(1)
- Tekin, Ilker(1)
- Tekin, İlker(1)
- Tigli, Ahmet(1)
- Tur, Kazim(1)
- Tuyan, Murat(1)
- Uslu, Emin(1)
- Yalçin, Önder(1)
- Yalçınkaya, Çağlar(1)
- Yanar, H.(1)
Yayınlar
- MakaleAçık Erişim2026Scopus SJRQ3Effects of Different Adhesive Ratios on Selected Panel Properties of High-Density Fiberboard (HDF) Produced from Fir and Beech Chips
Çamlıbel, Osman; Ayata, Ümit
High-density fiberboard (HDF) has been utilized in various forest-based industries for centuries. This study investigated the effects of different adhesive ratios on the properties of HDF through a series of tests. The panels, designed in particular for this study, had been produced in a laboratory putting the usage of a combination of 70% fir (Abies nordmanniana subsp. bornmulleriana) and 30% beech (Fagus orientalis L.) fibers sourced from the western Black Sea area of Turkey. Two adhesive levels were tested: 10.73% for panel I and 11.30% for panel II, both calculated based on dry fiber weight. We assessed several physical and mechanical properties, including density, modulus of rupture (MOR), modulus of elasticity (MOE), internal bonding (IB), hardness, water absorption, and through-thickness swell, in accordance with standard testing methods. The results indicated that both adhesive levels produced panels meeting the general performance requirements for HDF. Panel II, which contained slightly more adhesive, demonstrated marginally better performance in specific strength and dimensional stability tests. Overall, the findings suggest that optimizing adhesive usage in industrial HDF production can help establish a balance between the performance requirements of the boards and cost-effectiveness in production.
- MakaleAçık Erişim2026Scopus SJRQ2Investigation of the Effect of Niobium Addition on Fluidity and Mechanical Properties in Casting of Aluminum Alloys
Çolak, Murat; Yalçin, Önder
Aluminum and its alloys are important engineering materials widely used in the defense industry, industrial production, and machinery industry. Depending on the increase in quality expectations from aluminum casting alloys, castings are made with different alloy element additions. In the study, the effects of Nb addition to A356 aluminum alloy on casting properties were investigated with experimental studies. The Nb addition rate in the alloy was determined as 0.03%, 0.06% and 0.1%. Four-channel fluidity mold with varying section thicknesses, spiral fluidity mold and mechanical test mold were used in casting experiments. As a result, with the addition of Niobium, an increase in maximum tensile strength and % elongation was observed, while a decrease in fluidity properties was observed.
AtıfScopus4WoS5OpenAlex4
İncele - MakaleAçık Erişim2026Scopus SJRQ3Optimization of Rotary Degassing Parameters to Improve Melt Cleanliness and Mechanical Properties in A356 Aluminum Alloy
Kutsal, U.; Çolak, M.; Sağnak, Y.; Bardakci, S.; Ammas, G.; Sarper, G.
Melt cleanliness is a critical factor that directly affects the quality of aluminum castings and becomes even more significant in recycling-oriented production, where high scrap utilization is inevitable. Increasing the proportion of scrap intensifies the risk of oxide films, inclusions, and gas porosity in the molten metal; therefore, efficient refining techniques are essential. In this study, the effects of rotary degassing parameters—including rotor speed, rotation time, and gas flow rate—on melt cleanliness of A356 aluminum alloy were systematically investigated. Experimental melts containing 20% primary and 80% scrap aluminum were treated under various degassing conditions using a commercial flux cleaning flux. Characterization was performed through the Reduced Pressure Test (RPT), bifilm index analysis, fluidity measurements, microstructural examinations, and mechanical testing (tensile test and Brinell hardness measurement). The results demonstrated that increasing the rotor speed from 200 rpm to 500 rpm significantly reduced both the density and bifilm indices, indicating a notable improvement in melt cleanliness. Furthermore, higher gas flow rate (10 L/min) and longer rotation time (10 min) provided additional but secondary improvements. Consequently, the optimization of rotary degassing parameters enhanced not only melt quality but also tensile strength and ductility. These findings offer practical insights for optimizing process control in recycling-based aluminum foundries.
- MakaleAçık Erişim2025Scopus SJRQ2Importance of Melt Cleaning Parameters on Reliability of Tensile Properties in A356 Alloy
Tigli, Ahmet; Uslu, Emin; Çolak, Murat; Dispinar, Derya
This study examines how melt treatment and pouring temperature affect the microstructure and mechanical properties of A356 aluminum alloy. Samples were cast under degassed, non-degassed, and upgassed conditions at 725, 750, and 775 °C. Melt quality was assessed using the reduced pressure test (RPT) and the bifilm index (BI), while microstructural features were analyzed via SEM and EDS. Tensile testing and Weibull statistics were used to evaluate mechanical performance and variability. Results showed that by improper degassing the reproducibility of mechanical properties decreased regardless of hydrogen content of the melt. When bifilm index (BI) was high (> 50 mm), the ductility was lowered and caused greater variability in strength and elongation. SEM confirmed large oxide films in samples, linked to the brittle fracture. The work also highlighted the importance of melt cleaning parameters for the reliability of cast aluminum alloys regardless of the hydrogen content.
AtıfScopus3WoS3OpenAlex3İncele - MakaleAçık Erişim2025Scopus SJRQ2Investigation of the Effect of Vanadium Addition on Mechanical Properties in A356 Aluminum Casting Alloys
Çeker, Merve; Çolak, Murat
The superior properties of aluminum alloys are further improved by the addition of different elements and gain new qualities. In the aluminum casting industry, vanadium (V) addition plays an important role to improve the mechanical and physical properties of these alloys. In this study, different amounts of V (0.03%, 0.06% and 0.1%) were added to A356 alloy, and its effects on mechanical properties and microstructure were investigated experimentally. The liquid metal degassing process was applied in all experiments in order not to affect the results of gases and inclusions in the liquid metal before casting. In the study, degassing was assessed by the Reduced Pressure Test (RPT). Tensile and hardness test specimens were performed with specimens obtained from mechanical test molds. When the results were examined, the elongation amount, which was 2.7% in A356 casting without addition, increased with the addition of V and reached a maximum value of 7.6% with 0.1% V addition. Tensile stress values were 137 MPa in A356 castings without addition, 159 MPa with 0.03% V addition, 168 MPa with 0.06% V addition and increased up to 185 MPa with 0.1% V addition.
AtıfScopus5WoS5OpenAlex5İncele - MakaleAçık Erişim2024Scopus SJRQ2Exploring alternative polymer materials for joint liners: a software-guided material selection
Yilmaz, Galip; Gerdan, Zeynep; Çolak, Murat
This study explores the alternative polymer materials and selection process for joint implant liners, focusing on applying CES Selector software to identify suitable polymer materials. CES Selector provides an easy-to-use interface. It offers multiple selection methods, including boundary values and property constraints. Seven materials were excluded from the analysis, resulting in 19 potential candidates, including unconventional options like EVOH, PCTA, PESU, PI, PPA, PPC, PPSU, and PSU. The materials underwent evaluation based on key criteria, including tensile strength, Young’s modulus, compressive strength, fatigue strength, and fracture toughness. Overall, TPU exhibited a remarkable combination of high mechanical strength and adaptable Young’s modulus, making it a top contender. However, in other evaluation criteria, PI surpassed TPU, solidifying its potential as a superior choice. This systematic approach provides valuable insights for engineers and designers seeking innovative materials for joint implant liners. The study results broaden the range of materials used in implant manufacturing, providing potential alternatives that offer better long-term durability and performance.
- MakaleAçık Erişim2024Scopus SJRQ2Effects of Recycled Asphalt Material and Natural Pozzolan as Additives of Hot-Mix Asphalt: A Field Study
Yilmaz, Bahadır; Şentürk, Mehmet Akif
Using existing resources more efficiently and effectively becomes important currently. The question of how to make the best use of resources arises in the choice between constructing new roads and improving deteriorated existing roads. It is also important to reduce the amount of consumption and cost of materials. This has emerged the need to use waste materials by recycling and reusing. In this study, a new hot-mix asphalt (HMA) mixture was developed using recycled asphalt pavement (RAP), which was obtained by excavating the surface of a road at the end of its service life, together with a waste material namely natural pozzolan (NP). The final obtained mixture was used as a wear layer on an active highway. Core specimens were extracted from the paved layer for one year and subjected to dynamic and mechanical laboratory tests. Adding NP improved the resistance of the HMA mixture under heavy seasonal effects and traffic loads. In addition, NP increased the tensile strength, making the HMA mixture more resistant to deformation than control and RAP HMA mixtures. Dynamic creep test results showed that the control asphalt mixture had the most deformation and that the RAP mixture with NP had the least. According to the laboratory results, NP addition increased the stability value of the control mixture by 40%. Especially in cold seasons, the role of NP was more evident. In the performance tests that were applied on core samples taken from the field, ITS values for September increased by 98%, and the deformation values obtained as a result of the dynamic creep test decreased by 12%. In summary, adding NP to RAP HMA improves the performance of the pavement and the cost-effectiveness of the environmentally friendly use of RAP in HMA.
AtıfScopus1WoS1OpenAlex1İncele - MakaleYayıncıda açık erişim2023Scopus SJRQ4Development of Alkali-Activated Binders from Recycling Regional Tuff and Marble Wastes
Tekin, İlker; Ciza, Baraka; Gökçe, H.S.
The sustainability goals of the developing world have led many industries to recycle their wastes and reduce emitting greenhouse gases. To contribute to these environmental responsibilities, this study has focused on the development of eco-friendly binder materials from regional ground tuff and marble wastes by the activation of sodium silicate (Na2SiO3) and sodium hydroxide (NaOH) or slaked lime (Ca(OH)2). The results of this study show that alkali-activated composites experienced expansion, drying shrinkage cracking, leaching, and efflorescence. The compressive strength values of the NaOH and Ca(OH)2-activated pastes reached up to 15 MPa and 9 MPa, respectively. A reduction in NaOH molarity improved the compressive strength, dimensional stability, and durability of tuff-based alkali-activated pastes.
AtıfScopus5OpenAlex3İncele - Derleme MakaleYalnız künye2023Scopus SJRQ1Nanomaterial and fiber-reinforced sustainable geopolymers: A systematic critical review
Ünal, M. T.; Gökçe, H. S.; Ayough, P.; Alnahhal, A. M.; Simsek, O.; Nehdi, M. L.
Global cement production is associated with a colossal environmental footprint due to its considerable carbon emissions, energy consumption, depletion of natural resources, and waste accumulation. Geopolymer based concretes (GCs) have emerged as revolutionary alternatives to ordinary Portland cement concrete with enormous potential ecological benefits. However, they suffer from deficiencies, such as their brittle behavior under flexural and tensile loads. Using different types of fiber reinforcement and nanomaterial additions in geopolymer composites (GCs) has recently gained considerable attention to enhance various engineering properties, improve crack resistance, toughness, and ductility of the geopolymer matrices. This systematic and critical review analyses the effects of different reinforcing fibers and nanomaterials on the compressive and tensile strengths, modulus of elasticity, and impact resistance of GCs, and highlights the associated microstructural features. It is shown that carbon, basalt, and steel fibers can impart considerable improvement in mechanical strength, modulus of elasticity, and impact resistance of GCs. Furthermore, the introduction of polyethylene fibers has been shown to induce complex cracking behaviors, thereby contributing to the strain-hardening capability of geopolymer matrices. The integration of nanomaterials into GCs has emerged as a powerful strategy for achieving substantial enhancements in mechanical performance. Optimal nanomaterial dosages, typically around 2%, have been identified, with the specific surface area of nanoparticles proving to be a crucial determinant of the resulting mechanical properties. Notably, nano-silica has exhibited pronounced macro-scale reinforcement effects, whereas nano-titanium has displayed the potential to significantly enhance gel micromechanical characteristics. Additionally, synergistic combinations of nanomaterials and fiber reinforcements have led to the development of novel and distinctive mechanical properties within GCs. The synthesis of these findings underscores current best practices, highlights areas requiring further investigation, and emphasizes the need for concerted research efforts to advance the knowledge and implementation of sustainable geopolymers. This review offers a comprehensive analysis of the effects of fiber reinforcements and nanomaterials on geopolymer composites, providing valuable insights for researchers and practitioners.
AtıfScopus43WoS37İncele - Yüksek Lisans TeziAçık Erişim2022Polipropilen lif donatılı geopolimer derin karıştırma kolonunun yanıt yüzey yöntemi ile optimizasyonu ve sıcaklık etkisinin araştırılması
Büşra Avlayan
Boyları 30m'ye varan derin karıştırma kolonları kohezyonlu ve kohezyonsuz zeminlerde sıkça kullanılan derin zemin iyileştirme yöntemlerinden biridir. Tamamen zemine gömülü halde çalışan derin karıştırma kolonları kürlerini oluşturuldukları zemin ortamından almaktadır. Bu durumda zemin derinliği boyunca değişen zemin sıcaklığı aynı zamanda derin karıştırma kolonlarının kür sıcaklığı olmaktadır. Derin karıştırma kolonlarının imal edildikleri bölgenin yıllık ortalama sıcaklığı, imalatın yapıldığı günün hava sıcaklığı, zeminin termal iletkenlik katsayısı gibi parametreler zemin derinliği boyunca sıcaklığın yüzey sıcaklığından farklı olmasında rol oynar. Bu nedenle çoğu zaman zemin derinliği boyunca sıcaklık yüzey sıcaklığından farklı olur. Bu durum derin karıştırma kolonlarında zemin derinliği boyunca kür sıcaklığının değişken olması durumunu doğurur. Bu da kolonların taşıma gücüne etki eder. Yapılan bu tez çalışmasında sıcaklık etkisinin yüksek plastisiteli kil içeren bir zemin ortamında polipropilen donatı katkılı geopolimer esaslı derin karıştırma kolonu harcının mekanik özelliklerine olan etkisinin incelenmesi amaçlanmıştır. Yapılan çalışma kapsamında Amerikan Karayolları İdaresi'nin (FHWA) derin karıştırma kolonları için önermiş olduğu numune hazırlama şekilleri dikkate alınarak 50 mm çapında ve 100 mm yüksekliğinde numuneler oluşturulmuş. Geopolimer malzemenin elde edilmesinde bağlayıcı olarak F sınıfı uçucu kül kullanılmıştır. Aktivatör olarak kütlece %50-%50 oranında 10 M NaOH ve Na2SiO3 çözeltileri kullanılmıştır. Çalışma üç aşamada gerçekleştirilmiştir. Birinci aşamada yanıt yüzey yöntemi kullanılarak maksimum serbest basınç dayanımını veren bağlayıcı miktarı ve aktivatör içeriği belirlenmiştir. Çalışmanın ikinci aşamasında optimum miktarda bağlayıcı ve aktivatöre farklı oranlarda 6mm uzunluğunda polipropilen donatı karıştırılarak elde edilen numunelerin serbest basınç dayanımı belirlenmiştir. Bu suretle maksimum serbest basınç dayanımını veren donatı içeriği elde edilmiştir. Çalışmanın üçüncü adımında ideal miktarları belirlenen bağlayıcı, aktivatör ve polipropilen lif katkıları ile zemin numuneleri hazırlanmıştır. Hazırlanan numuneler 5°C, 10°C, 20°C ve 30°C'lik kür sıcaklıklarında 7 gün ve 28 gün kürlenmiştir. Kürlenen numuneler serbest basınç deneyleri ve üç eksenli basınç deneylerine tabi tutulmuştur. Bu suretle sıcaklık etkisinin serbest basınç dayanımı, elastisite modülü, içsel sürtünme açısı ve kohezyon parametrelerine olan etkisi incelenmiştir. Yapılan çalışma sonucunda numunelerin mekanik özelliklerinin 20°C'lik kür sıcaklığına kadar artan sıcaklıkla birlikte dikkate değer şekilde arttığı, bu sıcaklık değerinin üzerinde mekanik özelliklerde büyük bir değişimin olmadığı görülmüştür.
- MakaleAçık Erişim2021Scopus SJRQ2An Experimental and Numerical Determination on Low-Velocity Impact Response of Hybrid Composite Laminate
Erbayrak, Engin; Yuncuoglu, Ercument Ugur; Kahraman, Yusuf; Gumus, Beril Eker
In this study, experimental and numerical investigations were carried out in order to determine the mechanical properties and impact response of hybrid composite laminate. The hybrid composite laminate was formed from plain woven carbon fiber reinforced epoxy (CFRE) and plain woven glass fiber reinforced epoxy (GFRE) fiber using VARTM (vacuum-assisted resin transfer molding) process. The mechanical properties of the hybrid composites were determined using tensile test device with a 1 mm/min loading rate at room temperature. In addition, hybrid composites were subjected to low-velocity impact test under different impact energy levels (10, 20, 30, 40 J) for determining the impact response. Moreover, mechanical properties and impact responses of CFRE and GFRE laminates were also determined to compare to those of hybrid composite (HCGFRE). Microstructure analysis was performed to investigate the damage surfaces of the fiber and matrix in the composite material subjected to impact and tensile forces. In numerical analyses, composite damage model (Mat 54) was utilized in LS-DYNA® explicit finite element program to simulate the impact behavior of CFRE, GFRE and HCGFRE laminates. Consequently, the tensile test results showed that hybrid composite laminate behaved more ductile than carbon composite laminate and it exhibited more brittle behavior than glass composite laminate. Also, it was determined that absorbed energy and impact load capacity of HCGFRE composite laminate are between absorbed energy and impact load capacity of CFRE and GFRE composite laminate. It was determined that numerical results indicate a similar tendency with the experimental results.
AtıfScopus12WoS13OpenAlex14İncele - MakaleAçık Erişim2021Scopus SJRQ1Investigation of mechanical properties of high-performance hybrid fiber concretes adding nanomaterials using with coarse aggregate
Öksüzer, Nurullah; Anil, Özgür; Aldemir, Alper; Şahmaran, Mustafa
High-performance hybrid fiber cement composites have more ductility and higher strength than traditional concrete. This is because crack development is limited due to multiple small cracks are formed instead of a single large crack as the fibers enter the matrix. It is customary to produce these concrete composites with fine aggregates. In this study, concrete composites with coarse aggregates were strived to be produced to gain some feasibility. To this end, different mixtures composed of different aggregate/binder ratios and different fly ash/binder ratios were designed. In order to compare the effectiveness of the combination of different fibers were utilized in these mixtures. The volumetric ratios of fibers (excluding reference samples) were kept constant at a value of 2%. For each mixture, four-point bending and compressive tests were performed. The increase in the aggregate ratio was observed to cause a more ductile flexural behavior in mixtures composed of PVA and steel fibers. In contrast, the ductility was reduced in mixtures with Nylon-mono and steel fibers. In addition, the ductility values were enhanced with the increase in FA/PC ratio. In addition, the possibility to use the cheaper Nylon-mono fibers in hybrid fiber mixtures was proved with optimization of aggregate-binder (A/B) and FA/PC ratios, enabling more feasible high-performance concrete mixtures.
AtıfScopus12WoS9OpenAlex13İncele - MakaleAçık Erişim2021Scopus SJRQ3Determination of some engineering properties of volcanic tuff using non-destructive method
Can, Ömer
Volcanic tuffs extracted from the quarries of Bayburt province in Turkey are of three different types locally identified as white, yellow and green Bayburt stones. This study was intended to estimate the compressive strength of white, yellow and green Bayburt stones by non-destructive testing methods. For this, non-destructive tests such as the nail penetration test (NPT), Schmidt rebound hammer (SRH) test and ultrasonic pulse velocity (UPV) test were performed. A uniaxial compression test was also performed so as to assess the accuracy of the results obtained from the non-destructive tests. For the NPT, nails manufactured for the gun having 27 and 39 mm length were used. In total, 45 nails were nailed and average the values were taken. Also, uniaxial compressive strength (UCS) and UPV tests were performed on 30 samples in total; furthermore, a total of 60 impacts for the SRH test were performed. The relationship between the results recorded from NPT and UCS, SRH and UPV was determined by regression analysis and comparison. The relative absolute errors between the measured values and the predicted values are below 4% for SRH-NPT comparison and below 9% for UPV-NPT comparison. This method of estimating the compressive strength, by using these non-destructive experiments, was appraised as suitable.
- MakaleAçık Erişim2021Scopus SJRQ2Characterization of properties of Vanadium, Boron and Strontium addition on HPDC of A360 alloy
Gursoy, Ozen; Colak, Murat; Tur, Kazim; Dispinar, Derya
The demand for lighter weight decreased thickness and higher strength has become the focal point in the automotive industry. In order to meet such requirements, the addition of several alloying elements has been started to be investigated. In this work, the additions of V, B, and Sr on feedability and tensile properties of A360 has been studied. A mold design that consisted of test bars has been produced. Initially, a simulation was carried out to optimize the runners, filling, and solidification parameters. Following the tests, it was found that V addition revealed the highest UTS but low elongation at fracture, while B addition exhibited visa verse. On the other hand, impact energy was higher with B additions.
AtıfScopus13WoS12OpenAlex14İncele - MakaleAçık Erişim2020Scopus SJRQ2Optical, morphological and nano-mechanical properties of chromium oxide thin films fabricated by radio frequency (RF) magnetron sputtering
Özen, Soner; Şenay, Volkan
In this research, two transparent chromium oxide thin films having different thickness values were simultaneously deposited on glass substrates by adjusting target-substrate distance by means of radio frequency (RF) magnetron sputtering technique. The effect of film thickness on optical, morphological and nano-mechanical properties of the produced thin films were analyzed by using UV-VIS spectrophotometer, interferometer, tensiometer and atomic force microscope. The transmittance and absorbance of the films were measured in the incident photon wavelength range of 300–1000 nm. The optical energy band gap value of the produced thin films was estimated to be approximately 4 eV from the obtained absorbance data via Tauc's method. According to the results obtained from nano-mechanical tests, the produced thin films were highly scratch resistant. From the wetting experiments, it was found that the surfaces of the films were hydrophilic.
AtıfScopus11WoS10OpenAlex11İncele - MakaleAçık Erişim2018Scopus SJRQ1Optimization of reactive powder concrete by means of barite aggregate for both neutrons and gamma rays
Gökçe, H. Süleyman; Yalçınkaya, Çağlar; Tuyan, Murat
High performance concrete has been often preferred in special engineering structures and in challenging composites products. Researchers have recently focused on the radiation shielding characteristics of these type concrete mixtures due to rising nuclear industry in the developing world. In the study, performance of reactive powder concrete was researched with regard to gamma-ray and neutron attenuation when its normal weight aggregate replaced with heavyweight aggregate (barite). For this purpose, reactive powder concrete mixtures were prepared 100% quartz aggregate, 100% barite aggregate and their blending 50–50%, by volume. Some physical and mechanical characteristics such as density, compressive strength, fracture energy, flexural strength and modulus of elasticity of the mixtures were determined. Gamma-ray attenuation coefficients and transmission thickness values were theoretically established for commonly known gamma energies (661.7, 1173.2 and 1332.5 keV). Optimization of the reactive powder mixtures was performed for both neutron and gamma-ray attenuation at 8 MeV. As a result, barite significantly increased the gamma-ray attenuation coefficients of reactive powder concrete. The mechanical performance of reactive powder concrete, however, was markedly reduced as a result of barite substitution. Replacement of quartz by barite aggregate has a more adverse impact on flexural strength than that of compressive strength. A mix that contains 40% barite aggregate of total aggregate volume was found as an optimum RPC mixture for simultaneously shielding neutrons and gamma rays.
AtıfScopus138WoS126OpenAlex141İncele - MakaleYalnız künye2016Scopus SJRQ1Optimization of strength, ductility and electrical conductivity of Cu-Cr-Zr alloy by combining multi-route ECAP and aging
Purcek, G.; Yanar, H.; Demirtas, M.; Alemdag, Y.; Shangina, D.V.; Dobatkin, S.V.
Properties of Cu-Cr-Zr alloy with ultrafine-grained (UFG) structure produced by equal-channel angular pressing (ECAP) via different routes have been investigated. Special attention was paid to the optimization of multi-functional structural, thermal, electrical and mechanical properties of the alloy by aging of UFG one. Multi-pass ECAP via different routes gives rise to the formation of a deformation-induced submicrocrystalline structure with the grain (subgrain) sizes in the range of 200-300. nm depending on applied routes which leads to high hardness and strength in the Cu-Cr-Zr alloy with reduced ductility. Amongst the applied routes, route-Bc was found to be the best processing path for achieving the lowest grain size, the highest hardness and strength. Aging of 8Bc-processed UFG samples increases the hardness and strength of Cu-Cr-Zr alloy while retaining an electrical conductivity comparable to that of aged coarse-grained (CG) one. A satisfactory electrical conductivity of 71%IACS without considerable loss of peak hardness was achieved after aging of 8Bc-processed UFG alloy at 425. °C for 240. min. The precipitation strengthened UFG alloy remains its stable behavior at elevated temperatures up to 450. °C.
AtıfScopus164WoS147OpenAlex151İncele - MakaleYalnız künye2016Scopus SJRQ1Properties of NaOH activated geopolymer with marble, travertine and volcanic tuff wastes
Tekin, Ilker
In this study, geopolymer composite pastes (GCM) were produced using wastes of marble, travertine and natural pozzolan, with 1 M, 5 M and 10 M NaOH as alkali-activator. Curing process were done at 20, 45 and 75 °C temperatures for 24 h in an oven. And after that GCMs were exposed to wet and dry condition separately. The strength tests were done on the 2nd, 3rd, 7th, 28th and 90th days of curing period. The compressive strengths of the specimens in the wet conditions were reduced depending on time, but in dry conditions were increased with curing time.
AtıfScopus137WoS117OpenAlex149İncele