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• MakaleAçık Erişim2026Scopus SJRQ2/r/bayburt/11432
  Investigation 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.

  AtıfScopus4·WoS5·OpenAlex4

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• MakaleAçık Erişim2026Scopus SJRQ2/r/bayburt/11272
  Relationship Between Aluminum Liquid Metal Quality and Defects

  Kutsal, Umit; Colak, Murat; Ertugrul, Onur

  Aluminum alloys are commonly used in various industries today. In order to produce defect-free high-quality alloys with sustainable processes, defects must be reduced, and liquid metal quality must be improved. There are various methods that can be used for the measurement of liquid metal quality. Some of which are density index, bifilm index, K-Mold index, PoDFA, Prefil, fluidity test, and thermal analysis. The relationship and validation between these methods are still not clear. In this study, the relationship between aluminum liquid metal quality and defects is analyzed. Three different conditions were utilized. These conditions are (1) before a controlled degassing, (2) after the controlled degassing and (3) after the liquid metal is transferred to the holding furnace. According to the results, it was observed that the reduction of bifilms index did not reduce other inclusions and did not always favorably affect other measurement methods. It was also observed that the reduction of bifilm index did not improve the porosity level. Moreover, it was found that elongation values are related to the largest defect diameters. Bifilm index are not the only factor affecting the elongation and the density index directly affects the defect distribution. K-Mold index has an impact as it shows macro-inclusions. However, bifilm index, density index, fluidity index and K-Mold index are not as sufficient as numerical calculation of defect size by computed tomography (CT). The main factor directly affecting the elongation and tensile strength was found to be the inclusion size and diameter in the CT result. Examination of the fracture surfaces revealed that oxide contents are present, and the oxygen orientations and aluminum orientations are compatible. This harmony is thought to be related to the orientation of the bifilms in the structure.

  AtıfScopus8·WoS8

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• MakaleAçık Erişim2026Scopus SJRQ2/r/bayburt/10920
  Experimental and Modeling Study of Fluidity in Ductile Iron (GGG40)

  Coşar, Mehmet; Şüküroğlu, Ebru Emine; Güngör, Kadir; Çolak, Murat

  Ductile irons (spheroidal graphite cast irons, SGI) are widely used in automotive and energy systems due to their high strength, ductility, and excellent machinability. The casting quality of these alloys largely depends on the flow and filling behavior of the molten metal, namely its fluidity. In this study, the effects of pouring temperature, filling time, and metallurgical quality on the fluidity of GGG40 ductile iron were investigated through both experimental and numerical approaches. Experimental trials were conducted at pouring temperatures of 1350 °C, 1400 °C, and 1450 °C; metallurgical quality levels of 10%, 50%, and 90%; and filling times of 5 s and 10 s. The fluidity lengths were measured and statistically evaluated. The results revealed that increasing the pouring temperature and metallurgical quality significantly improved fluidity, while shorter filling times allowed the molten metal to travel longer distances before solidification. Modeling studies performed using a commercial casting simulation software showed strong correlation with the experimental data. Microstructural examinations indicated that higher pouring temperatures and improved metallurgical quality led to a more homogeneous distribution of graphite nodules and an increased ferrite fraction in the matrix. The findings provide valuable insights into the influence of process parameters on the fluidity behavior of ductile iron and offer critical design data for enhancing casting quality and productivity in industrial foundry applications.

  AtıfScopus1

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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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• MakaleAçık Erişim2025Scopus SJRQ2/r/bayburt/12790
  Importance 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.

  AtıfScopus3·WoS3·OpenAlex3

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• MakaleAçık Erişim2025Scopus SJRQ2/r/bayburt/11541
  Evaluation of Fe Content on the Fluidity of A356 Aluminum Alloy by New Fluidity Index

  Durmuş, Melek; Dispinar, Derya; Gavgali, Mehmet; Uslu, Emin; Çolak, Murat

  Elements that are deliberately added to aluminum alloys or are incorporated into the alloy later depending on the production process affect the final product properties. In addition, liquid metal cleaning is important in minimizing undesirable elements. Considering the production process, one of the most harmful impurities that is likely to pass into the alloy via diffusion for aluminum is the element, Fe. It is known that this is due to the fact that although Fe is highly soluble in liquid aluminum and its alloys, it has very little solubility in solids. Depending on the Fe content, mechanical properties, porosity and fluidity properties are affected in aluminum alloys. In this study, stainless and carbon steel rods were dipped into the melt at 700 °C and 750 °C for 1, 2 and 5 h. Castings were performed before and after degassing. Four-channel fluidity mold with different section thickness was used in the trials. Additionally, microstructure characterization was performed under varying casting conditions. Fluidity Index was proposed which is a single value measured from all fluidity values in different sections. When the results were examined, it was determined that the diffusion material, holding time, casting temperature and liquid metal cleanliness had an effect on the fluidity. Due to the increase in diffusion time, a decrease in fluidity was observed in both carbon steel and stainless steel. It was found that fluidity was significantly reduced when using stainless steel.

  AtıfScopus14·WoS14·OpenAlex15

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• MakaleAçık Erişim2025Scopus SJRQ2/r/bayburt/11513
  Investigation of the Effects of Filling Speed, Casting Temperature and Metallurgical Quality on Fluidity of Lamellar Graphite Cast Iron at Different Section Thicknesses

  Köse, Sami; Çolak, Murat; Şüküroğlu, Ebru Emine

  In this study, the fluidity properties of the alloy were investigated at different casting temperatures, different section thicknesses, and varying casting parameters of lamellar graphite cast iron materials. To achieve our goal, we utilized sand molds that were created with specific parameters including pouring temperature, metallurgical quality, section thickness, and fluidity test model. These molds were used for casting. Thus, the effect of fluidity properties in changing casting conditions and liquid metal advance distances at determined section thicknesses was investigated. Modeling was carried out with FlowCast casting simulation software by determining the liquid metal advance distance depending on the section thickness in the castings made in sand molds under changing casting conditions. The fluidity and advance distance of the liquid metal was determined comparatively with experimental and modeling techniques under the changing casting conditions in the parameters determined in this study. When the outcomes were examined; it was observed that different liquid metal advance distances occur at different cross-section thicknesses depending on the changing conditions.

  AtıfScopus8·WoS8·OpenAlex7

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• MakaleAçık Erişim2025Scopus SJRQ2/r/bayburt/10988
  Investigation 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.

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