Sürdürülebilir Kalkınma Amaçları

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  • MakaleAçık Erişim2025Scopus SJRQ2
    Microstructure and Mechanical Properties Change of Al7SiMgxEr (x: 0.03–0.1)

    Colak, Murat; Muhammed, Enes Aydin; Turkmen, Mustafa; Dispinar, Derya

    Aluminum and its alloys are widely used in many fields, such as automotive, aerospace, and defense industries, due to their many advantages. Due to such critical applications, the quality demands are also increasing. With the recent development in technologies, studies on casting of aluminum with different alloying element additions are ongoing rapidly. Various elements are added to the alloy to provide the desired properties. In this study, the effects of 0.03, 0.06, and 0.1 wt% Er addition to A356 aluminum alloy were evaluated simply because in the literature, only 0.1 wt% and above additions were studied. Samples were prepared using permanent molds and subjected to mechanical testing and microstructural characterization. Changes in the microstructure (evaluated via SDAS and SDAL) and mechanical properties of the cast specimens were analyzed. The results showed that Er addition improved tensile strength by up to 30%, increased elongation fourfold, and enhanced toughness by a factor of 4.5.

  • MakaleAçık Erişim2025Scopus SJRQ2
    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.

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  • MakaleAçık Erişim2025Scopus SJRQ2
    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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  • MakaleAçık Erişim2021Scopus SJRQ1
    Development of buffalo milk ice-cream by high pressure-homogenisation of mix: Physicochemical, textural and microstructural characterisation

    Sert, Durmuş; Mercan, Emin; Kılınç, Mehmet

    This study aimed to determine the physicochemical, textural, and microstructural characteristics of buffalo milk ice cream produced from high-pressure homogenisation (HPH) treated ice cream mix. Ice cream mix was subjected to 0 (control), 30, 60, 90, 120, or 150 MPa. HPH increased the firmness and consistency value of mixes, whereas it decreased cohesiveness and index of viscosity values. Also, HPH improved the lightness, redness, and yellowness of the mix. The mean particle size of HPH-treated mix samples was lower than the control, except HPH-150. The hardness of ice cream samples was between 14.30 and 77.81 N, in which HPH increased hardness value with the increasing pressure. The overrun of ice cream samples ranged from 19.93 to 45.15%, and HPH decreased it. HPH significantly improved resistance to melting in the ice cream. Scanning electron microscopy images revealed that HPH reduced the size of air bubbles. HPH at 150 MPa resulted in a foamy structure in the ice cream. HPH can alter the hardness, microstructure, and melting characteristics of buffalo milk ice cream. Products with improved properties may be developed by further modifying the formulation and processing parameters.

    • SDG 2 · Açlığa Son
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  • MakaleAçık Erişim2018Scopus SJRQ2
    Effect of grain refinement and phase composition on room temperature superplasticity and damping capacity of dual-phase Zn-Al alloys

    Demirtas, Muhammet; Atli, Kadri C.; Yanar, Harun; Purcek, Gencaga

    The effects of grain refinement and phase composition on superplasticity and damping capacity of eutectic Zn-5Al and eutectoid Zn-22Al alloys were investigated. For grain refinement, equal-channel angular pressing (ECAP) was applied to these alloys. ECAP completely eliminated the as-cast lamellar microstructures of both alloys and resulted in ultrafine-grained structures along with room temperature superplasticity. Furthermore, these microstructural changes with ECAP increased the damping capacity of both alloys in the dynamic hysteresis region, where damping arises from viscous sliding of phase/grain boundaries. Dynamic recrystallization at the surface and thermally activated viscous motion of grain/phase boundaries at the subsurface of the samples of both alloys were proposed as the damping mechanisms in the region where the alloys showed combined aspects of static/dynamic hysteresis damping behavior. Although the grain size is larger in Zn-5Al compared to Zn-22Al, it showed higher damping capacity due to the different sliding characteristics of its phase boundaries.

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  • MakaleAçık Erişim2017Scopus SJRQ1
    Effect of high pressure homogenization (HPH) on microstructure and rheological properties of hazelnut milk

    Gul, Osman; Saricaoglu, Furkan Turker; Mortas, Mustafa; Atalar, Ilyas; Yazici, Fehmi

    The effect of high pressure homogenization (HPH) on microstructure and rheological properties of hazelnut milks was investigated. Hazelnut milk samples were produced from cold pressed hazelnut cake and homogenized up to 150 MPa pressure. Microstructural and rheological properties of products, except temperature sweep, were greatly affected by HPH treatments. Homogenized samples showed significant reduction in particle size, which turned from bimodal and poly-disperse to monodisperse distributions. HPH decreased the consistency of products from 91.82 to 0.51 Pa.sn and increased flow behavior index from 0.15 to 0.36. All samples showed higher values G′ than G″, which indicates that samples could be classified as soft-gel network, and hazelnut milk samples did not obey the Cox-Merz rule without multiplying angular frequency with shift factor. In conclusion, HPH can be used to reduce the consistency of samples and the friction loss, thus minimizing the amount of energy required to flow during processing and distribution. Industrial relevance. Vegetable based beverages are available at any supermarket as an alternative to dairy products with an increasing consumer acceptance. Between these beverages hazelnut milk samples are the most noteworthy products due to important role in human nutrition and health, and moreover due to well accepted and widely consumed product. Due to its composition, hazelnut milks have very high consistency, and therefore, the energy consumption for processing and handling is too high. In this research, the high pressure homogenization (HPH) technology was successfully proposed to be used for improving microstructural properties, and hence reducing its consistency. The energy consumption during processing and distribution can be minimized by reducing the consistency and friction losses of product.

    • SDG 2 · Açlığa Son
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  • MakaleAçık Erişim2016Scopus SJRQ1
    Effects of in situ exopolysaccharide production and fermentation conditions on physicochemical, microbiological, textural and microstructural properties of Turkish-type fermented sausage (sucuk)

    Dertli, Enes; Yilmaz, Mustafa Tahsin; Tatlisu, Nevruz Berna; Toker, Omer Said; Cankurt, Hasan; Sagdic, Osman

    In this work, the role of in situ exopolysaccharide (EPS) production under different fermentation conditions on physicochemical, microbiological, textural and microstructural properties of sucuk was determined. For this purpose, the effect of EPS producing strains (control, strain 1, strain 2 and mixture) and fermentation conditions (fermentation temperature; 14, 16 and 18 °C and time; 8, 12 and 16 days) on physicochemical, microbiological, textural and microstructural properties were investigated using response surface methodology. In situ EPS production was observed to remarkably affect these properties while fermentation conditions were also seen to dominantly influence the physicochemical properties of sucuk, revealing that the ripening temperature appeared to be more determinant factor. EPS producing cultures enhanced the textural properties of sucuk which became harder, less adhesive and tougher. The microstructural analysis revealed the formation of web-like structure by in situ EPS production in sucuk mix during fermentation process. This study revealed the importance of in situ EPS production on final technological properties of sucuk.

    • SDG 2 · Açlığa Son
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