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• MakaleAçık Erişim2026Scopus SJRQ2/r/bayburt/11423
  Investigation of radiation shielding parameters of AZ61 magnesium alloy after electric arc spray and micro arc oxidation processes

  Durna, İdris; Yılmaz, Demet; Çatar, Recep; Altun, Hikmet

  In this study, the radiation shielding parameters of AZ61 magnesium (Mg) alloy, which is used in automotive, aerospace, and biomedical fields due to its low density, high specific strength, and biocompatible properties, were determined to investigate its usability in nuclear protection applications. Firstly, Al coating was applied to AZ61 Mg alloy by electric arc spray process and then ceramic oxide layer was obtained by micro arc oxidation (MAO) method. Then, the radiation shielding properties of AZ61 alloy were investigated. The radiation shielding parameters such as mass attenuation coefficient (MAC), mean free path (MFP), half-value layer (HVL) and effective atomic numbers (Zeff) were measured in gamma spectrometer with Ba-133 radioactive sources. The fast neutron removal cross-sections (ΣR), exposure buildup factors (EBF) were theoretically determined. The results revealed that the duplex coating (AZ61-Al-O) significantly enhanced the gamma shielding capability compared to the uncoated AZ61 alloy, achieving about 8.0 % higher MAC at 383.8 keV. Therefore, the AZ61-Al-O sample can be considered a promising lightweight material for radiation protection applications.

  AtıfScopus3·WoS3·OpenAlex4

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• MakaleYalnız künye2026Scopus SJRQ2/r/bayburt/10864
  Effect of Scandium Addition on Recycled A356 Alloy: Experimental Investigation and CALPHAD-Based Thermodynamic Analysis

  Kutsal, Ümit; Barutçuoğlu, Burak; Sağnak, Yiğit; Toker, Abidin; Çatar, Recep; Çolak, Murat

  This study systematically investigates the influence of scandium (Sc) additions at 0.1, 0.2, and 0.3 wt.% on the melt quality, microstructural characteristics, fluidity, and mechanical performance of A356 aluminum alloy under recycling-oriented casting conditions. The alloy charge consisted of 20% primary aluminum and 80% recycled scrap, while the Fe content was maintained at 0.2 wt.%. Melt treatment was performed by rotary degassing using a commercial flux. Melt quality was assessed using the Reduced Pressure Test (RPT) and bifilm index analysis, whereas casting performance was evaluated through an eight-channel fluidity test. Mechanical behavior was characterized by tensile and Brinell hardness testing, and microstructural and phase analyses were conducted using scanning electron microscopy (SEM) and X-ray diffraction (XRD). To complement the experimental investigation and provide a thermodynamic basis for interpretation, phase stability, solidification behavior, and phase-fraction evolution were examined using Thermo-Calc within the CALPHAD framework. By combining experimental characterization with computational thermodynamic analysis, this study elucidates the effect of Sc content on the processing–microstructure–property relationships of recycled A356 alloys and provides a systematic basis for evaluating Sc modification in high-recycled-content aluminum castings.

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  İncele
• MakaleAçık Erişim2025Scopus SJRQ2/r/bayburt/11558
  Investigation of the Structural and Corrosion Properties of Duplex Surface Treated AZ31 Magnesium Alloy

  Durna, İdris; Çatar, Recep; Altun, Hikmet

  The AZ31 alloy was first completely coated with pure aluminum in this study using the electric arc spray coating method. Then, considering the existing benefits of the micro-arc oxidation process (MAO), a ceramic oxide coating was formed by applying MAO to the Al-coated surface. Thus, a duplex coating was obtained on the base material. The structural properties of both the Al-coated samples and the duplex coatings obtained after the MAO process were investigated by scanning electron microscopy, energy-dispersive x-ray analysis (EDS), and x-ray diffraction devices. The electrochemical behavior of the coatings was carried out in a 3.5 wt.% NaCl solution. The samples were polarized from the potential value − 0.2 V below the corrosion potential to the maximum value of 2 V at a scanning rate of 1 mV/s, and potentiodynamic polarization curves were recorded. According to the electrochemical experiments, Al coatings and duplex coatings improved the corrosion resistance of AZ31 alloy. The corrosion current density values ​​were 298.23 µA/cm2 for the base material, 0.415 µA/cm2 for the Al coating, and 0.014 µA/cm2 for the duplex coating, respectively. The best corrosion resistance among all samples was obtained in duplex-coated samples obtained by MAO. Due to their low corrosion resistance, magnesium alloys are restricted in many areas, especially aviation, automotive, and biomedical. Therefore, this study aimed to improve the corrosion resistance of AZ31 magnesium alloy.

  İncele
• MakaleAçık Erişim2025Scopus SJRQ4/r/bayburt/11424
  Effect of Plasma Electrolytic Oxidation Process on Corrosion Resistance of Al-Coated AZ61 Magnesium Alloy

  Durna, İdris; Çatar, Recep; Altun, Hikmet

  Magnesium alloys are extensively utilized in aerospace, aviation, and automotive sectors due to their low density and high specific strength, which offer significant advantages for lightweight structural applications. Their low density especially directs the attention of the aviation sector, where lightness is necessary, to these alloys. However, one of the disadvantages that restricts their use in the industry is their low corrosion resistance. In this study, the Plasma Electrolytic Oxidation (PEO) process was applied in a silicate-based electrolyte to AZ61 magnesium alloy pre-coated with aluminum using the electric arc spraying technique. To examine the characteristics of the fabricated coatings, their phase structures, surface features, and elemental compositions were investigated through XRD, SEM, and EDS analyses. Corrosion performances of coatings were investigated by potentiodynamic polarization test in 3.5% NaCl solution. As a result of electrochemical tests, corrosion current density values for the base sample (AZ61) and PEO coating (AZ61-PEO) were determined as 36,29 μA. cm−2 and 6,53 μA. cm−2, respectively. The findings highlight that the Al₂O₃ layer formed following PEO treatment significantly enhanced the corrosion resistance compared to the base sample.

  İncele
• MakaleYalnız künye2022Scopus SJRQ2/r/bayburt/11887
  Improvement of corrosion and stress corrosion properties of magnesium alloys by coating aluminum with the electric arc spray method

  Catar, Recep; Altun, Hikmet

  In this study, corrosion and stress corrosion behaviors of AZ31, AZ61, and AZ91 magnesium alloys coated with aluminum by the electric arc spray method were investigated in 3.5 wt.% NaCl solution. Structural properties of coated materials were investigated by scanning electron microscopy (SEM), energy dispersive X-ray analysis, and X-ray diffraction. Electrochemical properties were determined using the potentiodynamic polarization method in 3.5 wt.% NaCl solution. Potentiodynamic polarization curves showed that corrosion current density values did not change with coating in aluminum-coated samples by the electric arc spray method. In contrast, corrosion potential value increased toward positive values. Slow strain rate test (SSRT) was used to determine the stress corrosion behavior and stress corrosion indexes (ISCC), ultimate tensile strength (UTS), and elongation of AZ31, AZ61, and AZ91 magnesium (Mg) alloys were determined. As a result of the SSRT, the aluminum coating process decreased significantly the stress corrosion indexes of AZ31, AZ61, and AZ91 Mg alloys. The fracture of surface images was also examined in the SEM, and both intergranular and transgranular stress corrosion cracking were observed in all three alloys.

  AtıfScopus6·WoS5·OpenAlex5

  İncele
• MakaleAçık Erişim2019Scopus SJRQ3/r/bayburt/13823
  Investigation of Stress Corrosion Cracking Behaviour of Mg-Al-Zn Alloys in Different pH Environments by SSRT Method

  Catar, Recep; Altun, Hikmet

  In this study, stress corrosion behaviors of AZ31, AZ61 and AZ91 Mg alloys which contain different amounts of Al were investigated under acidic, basic and neutral environments having chloride ions using Slow Strain Rate Test (SSRT) method. Stress corrosion indexes (ISCC), ultimate tensile strength (UTS) and elongation of AZ31, AZ61, and AZ91 Mg alloys were determined and compared. Slow strain rate test showed that three Mg alloys in basic environments were the least stress corrosion susceptible, while the most stress corrosion susceptible occurred in acidic environments. Also, it has been shown that the stress corrosion indexes of AZ91 Mg alloys are less than AZ31 and AZ61 Mg alloys in all environments. UTS and elongation of AZ61 Mg alloys were higher than those of AZ31 and AZ91 in all media. The fracture of surface images also examined in the scanning electron microscope (SEM) and both intergranular stress corrosion cracking (IGSCC) and transgranular stress corrosion cracking (TGSCC) were observed in all three alloys.

  AtıfScopus16·WoS13·OpenAlex14

  İncele
• MakaleYalnız künye2017Scopus SJRQ2/r/bayburt/12602
  Optimum design of steel bridges including corrosion effect using TLBO

  Artar, Musa; Catar, Recep; Daloglu, Ayse T.

  This study presents optimum design of plane steel bridges considering corrosion effect by using teaching-learning based optimization (TLBO) method. Optimum solutions of three different bridge problems are linearly carried out including and excluding corrosion effect. The member cross sections are selected from a pre-specified list of 128 W profiles taken from American Institute of Steel Construction (AISC). A computer program is coded in MATLAB to carry out optimum design interacting with SAP2000 using OAPI (Open Application Programming Interface). The stress constraints are incorporated as indicated in AISC Allowable Stress Design (ASD) specifications and also displacement constraints are applied in optimum design. The results obtained from analysis show that the corrosion effect on steel profile surfaces causes a crucial increase on the minimum steel weight of bridges. Moreover, the results show that the method proposed is applicable and robust to reach the destination even for complex problems.

  AtıfScopus9·WoS9·OpenAlex2

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