Sürdürülebilir Kalkınma Amaçları

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• MakaleAçık Erişim2025/r/gumushane/19803
  Toz metalurjisi yöntemiyle üretilen Al-Cu-Mg alaşımlarının mikroyapı ve tribolojik özelliklerinin incelenmesi

  Beder, Murat

  Bu çalışmada, Al-Cu-Mg alaşımı 450oC (A), 500oC (B) ve 550oC (C) sıcaklıklarında sıcak presleme işlemine tabi tutulmuştur. Sıcak presleme yöntemi kullanılarak yoğunlaştırılan A, B ve C kodlu numunelerin sıcak pres sonrası mikro yapısı ve tribolojik özelliklerinin incelenmesi gerçekleştirilmiştir. Deneyler sonucunda elde edilen mikro yapı incelemelerinde A kodlu numunedeki porozite miktarının B ve C kodlu numunelerdeki porozite oranına göre yüksek olduğu ve artan presleme sıcaklığı ile yoğunluğun doğru orantılı olarak arttığı belirlenmiştir. Buna ek olarak artan pres sıcaklığı ile birlikte iç yapıda bulunan α-Al fazının nispeten daha düzgün ve eş taneler şeklinde yapıya homojen dağıldığı gözlenmiştir. En yüksek sertlik değeri 550oC’de sıcak presleme işlemine tabi tutulan C kodlu numunede elde edilmiştir. Buna göre, C numunesinin sertlik değeri B kodlu numuneye göre %20, A kodlu numuneye göre %26, mikro sertlik değeri ise B kodlu numuneye göre %30 A kodlu numuneye göre %33’lük bir artış sergilemiştir. Ayrıca A, B ve C kodlu numunelerin yoğunluk değerleri sırasıyla, 2.7554, 2.7640 ve 2.7655 gr/cm3 olarak belirlenmiştir. Yapılan sürtünme ve aşınma testlerinden elde edilen hacim kaybı-çevrim sayısı verilerine göre en düşük aşınma direnci A numunesinde, en yüksek aşınma direnci ise C numunesinde elde edilmiştir. Buna göre 25x103, 50x103 ve 75x103 çevrim sayısındaki C kodlu numune A numunesine göre sırasıyla %39, %23 ve %45 daha yüksek aşınma direnci sergilemiştir. Farklı sıcaklıklarda presleme işlemi yapılan A, B ve C numunelerinin aşınma yüzeylerinin, aşınma parçacıklarının ve bilye yüzeylerinin benzer görüntü sergilediği belirlenmiştir. Buna göre aşınma yüzeyleri sıvama tabakalarından ve soyulmalardan, aşınma parçacıklarının irili ufaklı tozlardan bilye yüzeylerinin ise sıvama tabakalarından meydana geldiği gözlenmiştir.

  İncele
• MakaleAçık Erişim2025/r/gumushane/13967
  The effect of high B4C ratio on the improvement of mechanical properties and wear resistance of Al2024/B4C composites fabricated by mechanical milling-assisted hot pressing

  Beder, Murat

  In this study, the effects of 0 wt% (C0), 10 wt% (C1), 20 wt% (C2) and 40 wt% (C3) B4C content on the microstructure, mechanical properties and dry wear properties of Al2024/B4C composites were investigated. In order to prepare Al2024 matrix composites with different B4C particle contents, mechanical milling (MM) and hot pressing (HP) were employed as powder metallurgy methods. It was found that the θ (CuAl2) phase content in the microstructure of Al2024/B4C compact materials increased with increasing B4C particle reinforcement, reaching its highest value at 40 wt% B4C (C3) reinforcement ratio. As the B4C particle reinforcement content increased, the hardness values of the composite samples increased. Flexural strength values were 445.30 MPa, 495.20 MPa, 277.59 MPa, and 129.37 MPa for samples coded C0, C1, C2, and C3, respectively. It was found that the C0 sample without particle reinforcement exhibited more than 10 times the volume loss of the C3 sample with the highest particle reinforcement at 450 m sliding distance. The SEM examination of the friction surfaces of the Al2024/B4C composite samples showed that the worn surfaces were composed of delamination, adhesion and smearing layers.

  İncele
• MakaleAçık Erişim2025/r/gumushane/12422
  The effect of high SiC ratio on the physical, mechanical, tribological and corrosion behavior of Al2024 alloy matrix composites fabricated by powder metallurgy

  Beder, Murat; Varol, Temel; Akçay, Serhatcan Berk; Çuvalcı, Hamdullah; Erdemir, Fatih; Khan, M Adam; Yıldız, Uğur Temel

  Reinforcing materials used in the production of metal matrix composites are used to improve the properties of the final composite. However, the compatibility between matrix and reinforcement and the reinforcement ratio directly affects the properties of the composite material. For this reason, low reinforcement ratios are preferred in many studies on ceramic particle reinforced composites. Unlike conventional studies, in this study, the effects of 10 wt%, 20 wt% and 40 wt% SiC content on the microstructure, dry wear properties and corrosion properties of Al2024 matrix composites were investigated. θ phase content became higher as the SiC content was increased. Hardness values increased with increasing SiC reinforcement. The highest value (307.68 HB) was obtained for the composite with 40 wt% SiC reinforcement, an increase of more than 100%. A decrease in volume loss with increasing SiC reinforcement was observed in the friction and wear tests. For 5 N of load and 1200 m of sliding distance, it was found that an addition of 40 wt% of SiC particles in Al2024 matrix results decrease in volume loss by almost 722%.

  İncele
• MakaleYalnız künye2025/r/gumushane/12271
  Effect of mechanical milling parameters on the properties of electrolytic pure copper powders and hot pressed billets fabricated from recycled copper wastes

  Akçay, Serhatcan Berk; Çuvalcı, Oğuzhan; Varol, Temel; Çuvalcı, Hamdullah; Kocaman, Mücahit; Alver, Ümit; Beder, Murat; Güler, Onur; Aksa, Hüseyin Can; Gasha, Shimelis Bihon

  This study was conducted to comprehensively investigate the effect of mechanical milling parameters on the properties of electrolytic pure copper powders and hot pressed billets fabricated from recycled copper wastes. Three different milling speeds, five different milling times and three different ball to powder weight ratios were used to fully reveal the effect of the mechanical milling process on the properties of recovered Cu powders. The results show that as the milling time and milling speed increased, the initial dendritic morphology of the copper was transformed into a flake-like structure. At 400 rpm and a 5:1 BPR parameters, the average particle sizes of C3, C4, and C5 after 2, 4, and 8h were ∼52 μm, 83 μm, and 71 μm, respectively. This suggests that particle size initially increases due to shape change and cold-welding, but at longer durations, fracture becomes dominant. The I5 with d(0.5) = 69.32 μm exhibited a high flow rate of 5.88 g/s with an apparent density of 2.9 g/cm3.While the hardness value of the Cu samples (A1-bulk sample) produced by exposure to the lowest deformation during the mechanical milling is 95.02 HB, the hardness value of the Cu specimens (F5-bulk sample) showing the highest apparent density, best flow rate and highest density values is 109.31 HB. The electrical conductivity values were determined to be approximately 52.2 MS/m, 57.4 MS/m and 44.3 MS/m for A1-bulk, F5-bulk and H5-bulk, respectively. This study offers valuable insights into the relationship between milling parameters, powder characteristics, and final material properties.

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  İncele
• MakaleAçık Erişim2024/r/gumushane/19959
  AlSi10Mg alaşımının içyapı ve mekanik özellikleri üzerine sıcak presleme yönteminin etkisi

  Beder, Murat

  Bu çalışmada, sıcak presleme yöntemi kullanılarak üretilen ve farklı presleme sıcaklıklarında yoğunlaştırılan AlSi10Mg alaşımının mikroyapısı ve mekanik özelliklerinin incelenmesi araştırılmıştır. Bu amaçla AlSi10Mg alaşımı numunelerine soğuk presleme (N0) ve 450 oC (N1), 500 oC (N2), 550 oC (N3) sıcaklarında sıcak presleme işlemi uygulanmıştır. Soğuk presleme yapılan N0 numunesindeki porozite miktarının N1, N2 ve N3 numunelerine göre yüksek olduğu ve artan sıcaklıkla yoğunluk değerlerinin arttığı, porozite miktarının ise azaldığı belirlenmiştir. Ayrıca, içyapı incelemelerinde artan sıcaklıkla birlikte içyapıdaki silisyum (Si) parçacıklarının giderek küreselleştiği ve yapı içerişe homojen bir şekilde dağıldığı gözlenmiştir. Buna göre, N0, N1, N2 ve N3 kodlu numunelerde en yüksek sertlik değerini yaklaşık %45’lik artış sergileyen N3 numunesi göstermiştir. Buna ilaveten N0, N1, N2 ve N3 numunelerinin yoğunluk değerleri sırasıyla 2.3523, 2.6165, 2.6191 ve 2.6287 gr/cm3 olarak belirlenmiştir. Çekme dayanım değerlerinde ise en yüksek çekme dayanım değeri N3 numunesinde 186 MPa olarak, en düşük çekme dayanım değeri ise N1 numunesinde 156 MPa olarak belirlenmiştir. Buna göre N3 numunesi N1 numunesine göre %20 oranında daha yüksek çekme dayanımı performansı sergilemiştir. Numunelere uygulanan bütün pres sıcakları için çekme ve darbe kırılma yüzeylerinin yarılma düzlemlerinden ve yırtılma sırtlarından oluştuğu belirlenmiştir. Ayrıca, çekme ve darbe deneylerinden elde edilen kırılma yüzeylerinde, artan presleme sıcaklığı ile sertliğin artmasından dolayı yarılma düzlemlerinin genişliklerinin arttığı tespit edilmiştir.

  İncele
• MakaleAçık Erişim2024/r/gumushane/14268
  Impact of high Al2O3 content on the microstructure, mechanical properties, and wear behavior Al–Cu–Mg/Al2O3 composites prepared by mechanical milling

  Beder, Murat; Varol, Temel; Akçay, Serhatcan Berk

  Metal matrix composites are increasingly being recognized as new wear-resistant materials. The main purpose of this study is to investigate the microstructure, mechanical properties, and wear resistance of Al–Cu–Mg alloy matrix composites reinforced with high contents of Al2O3 particles. Moreover, the effects of 10, 20, and 40 wt% Al2O3 contents on the microstructure, mechanical properties, and dry wear resistance of the Al–Cu–Mg matrix composites are studied. The results show that the θ (CuAl2) phase ratio increases with increasing Al2O3 contents. The hardness values of the samples also increase with increasing Al2O3 contents. The highest tensile and flexural strengths are measured as 284 and 562.9 MPa, respectively, and these values are obtained for the composite material reinforced with 10 wt% Al2O3 particles. The continuous increase in the hardness of the samples with increasing Al2O3 content may cause the lowest volume loss for the 40 wt% Al2O3-reinforced composite. The friction surfaces show that the wear surfaces comprise adhesion, delamination, and smear layers. Overall, compared to the Al2O3-reinforced composite samples, pure Al–Cu–Mg alloy samples show approximately 2 times more mass gain.

  İncele
• MakaleAçık Erişim2024/r/gumushane/14107
  The Effect of Heat Treatment on the Mechanical Properties and Oxidation Resistance of AlSi10Mg Alloy

  Beder, Murat; Akçay, Serhatcan Berk; Varol, Temel; Çuvalcı, Hamdullah

  In this study, the microstructure, hardness, tensile strength, and dry wear properties of the cast AlSi10Mg alloy as well as the effects of processing parameters on the oxidation behavior of this alloy were investigated. In this context, AlSi10Mg (wt%) alloy was produced by gravity die casting method, and then, air cooling, quenching, and T6 treatment were applied. The microstructure of the alloy was investigated using an optical microscope, SEM, and EDS. Additionally, thermogravimetric analysis (TGA) was used to determine the effect of processing parameters on the oxidation behavior of the samples. The friction and wear properties of the alloy were investigated using a ball-on-disk wear test device. It was founded that the as-cast AlSi10Mg alloy's microstructure contained phases of α(Al), Si, and β-Mg2Si. It has been observed that the microstructure of the cast AlSi10Mg alloy gradually turns into a spherical form when quenching and air-cooling heat treatments are applied. Also, T6 heat treatment led to further spheroidization of Si particles, formation of β-Mg2Si precipitates, and elimination of the Chinese script morphology of the β-Mg2Si phase. It was observed that the yield strength of the AlSi10Mg alloy in the as-cast state decreased negligibly compared to the air-cooled state, while there was an increase of up to 70% in the aging-treated condition. The results show that the tensile strength of the as-cast AlSi10Mg alloy increased by 115% after aging. Additionally, it was found that the AlSi10Mg alloy's wear resistance increased with the aging process.

  İncele
• MakaleYalnız künye2024/r/gumushane/12675
  Influence of post processing on the mechanical properties and wear behavior of selective laser melted Co-Cr-Mo-W alloys

  Varol, Temel; Aksa, Hüseyin Can; Yıldız, Fatih; Akçay, Serhatcan Berk; Kaya, Gürkan; Beder, Murat

  In the study, the effect of laser energy density and post-processes (sintering, cold rolling, and hot rolling) on the properties of Co-Cr-Mo-W alloys fabricated by selective laser melting (SLM) are investigated. The samples are fabricated at 83, 125, and 167 J/mm3 of laser energy density to compare their properties. XRD results show that the samples in which ε-Co martensitic phase dominates γ-Co phase are the samples exposed to hot rolling. The highest hardness values obtained with the hot rolling applied after SLM. The hardness for SLM1hr, SLM2hr and SLM3hr is 489.2, 500.4 and 509.8 HV, respectively. The lowest wear rate values are also obtained after the hot rolling post-process, where the highest hardness values and lowest average COFs were obtained.

  İncele
• MakaleAçık Erişim2024/r/gumushane/11742
  Prediction of effect of fabrication parameters on the properties of B4C ceramic particle reinforced AA2024 matrix nanocomposites using neural networks

  Varol, Temel; Çanakçı, Aykut; Özşahin, Şükrü; Beder, Murat; Akçay, Serhatcan Berk

  In the present study, a prediction model was created to predict the impact of B4C content, milling time and matrix size on the hardness and density of AA2024-B4C nanocomposites produced by means of flake powder metallurgy. The process involved synthesizing AA2024-B4C nanocomposite powders by mechanical milling followed by preparing nanocomposites by hot pressing. The matrix size of the AA2024 alloy powders, the milling time, and the B4C content were selected as the input parameters. On the other hand, the density and the hardness of the AA2024-B4C nanocomposites were designed as the output parameters. The results showed that the sintered density is significantly improved by decreasing matrix size. It was found that density of AA2024–3 wt%B4C nanocomposites is lower than AA2024–1 wt%B4C nanocomposites. However, the hardness of AA2024–3 wt%B4C nanocomposites is better than AA2024–1 wt%B4C nanocomposites. The AA2024-B4C nanocomposite prediction model could predict hardness and density with a mean absolute percentage error (MAPE) of 0.32% and 1.38%. The results show that the ANN model is a useful tool for the matrix size effect prediction, milling time and B4C content on the density and hardness of AA2024-B4C nanocomposites prepared by flake powder metallurgy.

  İncele
• MakaleAçık Erişim2021/r/gumushane/13281
  Influence of Mg addition and T6 heat treatment on microstructure, mechanical and tribological properties of Al–12Si–3Cu based alloy

  BEDER, M.; ALEMDAG, Y.

  The aim of the present study was to investigate the influence of Mg addition and T6 heat treatment on microstructure, mechanical and tribological properties of the Al–Si–Cu–Mg alloys. In this context, a series of Al–12Si–3Cu–(0.5–2.5)Mg (wt.%) alloys were produced by permanent mould casting, and then subjected to T6 treatment. Their microstructure and mechanical properties were investigated using OM, XRD, SEM, EDS along with hardness, tension, compression and Charpy impact tests. Dry sliding friction and wear properties of the alloys were studied using a ball-on-disk type tester. It was observed that the microstructure of as-cast Al–12Si–3Cu–Mg alloys consisted of α(Al), Si, θ-CuAl2, β-Mg2Si, Q-Al5Mg8Cu2Si6 and π-Al8Mg3FeSi6 phases. T6 heat treatment gave rise to nearly spherodization of eutectic Si particles, formation of finer θ-CuAl2 and β-Mg2Si precipitates and elimination of Chinese script morphology of β-Mg2Si phase. The addition of Mg up to 2.5 wt.% decreased the hardness, tensile and compressive strengths, tensile elongation and impact toughness of the as-cast and T6-treated alloys and increased their friction coefficient and volume loss. T6 treatment, on the other hand, led to a significant increase in mechanical properties and wear resistance of as-cast alloys.

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