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    Automatic and Rapid Measurement in Artificial Intelligence-Aided Microstructure Analysis: A Deep Learning Approach Applied to AlSi9 Alloys
    (Springer Heidelberg, 2025) Kalkan, Mahmut Furkan; Kalkan, Ibrahim Halil; Yilmaz, Necip Fazil; Dispinar, Derya; Kahruman, Cem; Yavuz, Abdulcabbar
    This study showcases a proof-of-concept of an artificial intelligence-driven analytical technique that facilitates the automated extraction of significant quantitative data from microstructural images. Semantic segmentation and classification were conducted on eutectic Si particles and dendritic architectures utilizing microscopic images of AlSi9 alloys with varying Sr ratios. Following segmentation, characteristics including area, aspect ratio, maximum Feret diameter, circularity and SDAS were assessed automatically, and the resulting values were compared with both literature and manual measurements. The samples were effectively categorized based on their alteration levels using a CNN-based classification algorithm. This technology provides significant temporal and financial benefits for microstructural investigation by executing the entire procedure autonomously and expeditiously. The minimal error rates and elevated accuracy findings demonstrate the usefulness and dependability of the devised method for automated microstructural analysis. This paper exemplifies the application of artificial intelligence-driven microstructural analysis techniques in materials science, addressing a significant gap in the literature.
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    Change in Porosity of A356 by Holding Time and Its Effect on Mechanical Properties
    (Springer, 2018) Uludağ, Muhammet; Cetin, Remzi; Gemi, Lokman; Dispinar, Derya
    In most of the practical casting operations, it is important to be able to cast large number of part with one single melt. Therefore, when quantity of the charge and melting crucible is increased, during casting process, the liquid is led to settle for a long period of time. In this work, 10kg charge of A356 was melted at 750 degrees C and held for 240min. A sand mold with different thickness was cast at 30, 60, 120, and 240min of holding time of the liquid, before and after degassing conditions. Melt quality was measured by reduced pressure test, and pore size and number were measured at each cast part. A correlation between bifilm index and tensile properties was established. It was found that melt quality was decreased with increased holding time and pore formation was enhanced linearly. Additionally, mechanical properties of the alloy were decreased with decreased melt quality and increased pore formation due to holding time of the liquid.
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    Change in Si morphology by T6 heat treatment and its effect on tribological properties of Al-Si alloys
    (Springer Heidelberg, 2026) Ozaydin, Merve; Dispinar, Derya; Uludag, Muhammet
    The effect of heat treatment on microstructural and mechanical properties of three different Al-Si alloys was investigated. Both sand and permanent molds were used to produce Al7Si, Al-12Si and Al-17Si alloy samples. Changes in microstructure, hardness, wear and surface roughness were evaluated. In T6 heat treatment, two different temperatures (425 degrees C and 500 degrees C) and three different durations (5, 15, and 30 h) were selected, and after quenching, aging was carried out at 190 degrees C for 16 h. It was found that increasing the heat treatment temperature and duration resulted in smaller silicon phases for all three alloys. This case positively affected the hardness, wear and surface roughness of the alloys. The best parameter for the morphology of Al7Si and Al-12Si alloys in sand casting samples was 500 degrees C solution temperature and 30 h. 425 degrees C solutionizing temperature was found to be insufficient for Si modification.
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    Change in the Oxide Structure of Al-12Si Melts in the Presence of Sr
    (2023) Kahruman, Cem; Alev, Ugur; Dispinar, Derya
    Bifilm defects are the surface entrained double oxide films that are introduced into melts during turbulence and disturbance to the surface of the melt. These defects lead to porosity formation if they are not cleaned from the melt. Thus, the characterisation of the dross that is formed on the surface of the melt becomes a key parameter. In this work, Sr containing Al12Si alloy was used. For the modification process, 100, 200 and 300 ppm Sr was added to the alloy. The oxidation tests were carried out in liquid state at 700, 750 and 800 °C for holding durations of 12, 24, 36 and 48 hours. The structure was characterised by optical microscopy, Scanning Electron Microscopy, X-Ray Diffraction and X-ray photoelectron spectroscopy techniques. It was found that after 12 hours of holding, spinel oxides were formed on the surface mainly SrO.Al2O3 and MgO.Al2O3.
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    Characterization of the Effect of Melt Treatments on Melt Quality in Al-7wt %Si-Mg Alloys
    (Mdpi Ag, 2017) Uludağ, Muhammet; Cetin, Remzi; Dispinar, Derya; Tiryakioglu, Murat
    The effects of degassing, holding time and melt additions (Sr, Sr + Ti, Ti, B and B + Sr) on the quality of A356 melts were examined. A total of 120 reduced pressure test samples were collected. Pores in these samples were analyzed via digital image processing to determine the number density of pores as well as the statistical distribution of their sizes. Results showed that in all cases, degassing with argon reduced the number of defects regardless of the additions made to the melts. Moreover, all additions were found to degrade melt quality. The lowest number density of pores in all melts was achieved in melts with no additions that were degassed. In both degassed and non-degassed melts, Sr additions degraded the melt quality significantly. The mechanisms of melt quality improvement or degradation with different melt treatments are discussed in the paper.
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    EFFECT OF DEGASSING AND GRAIN REFINEMENT ON HOT TEARING TENDENCY IN Al8Si3Cu ALLOY
    (Springer International Publishing Ag, 2018) Uludağ, Muhammet; Cetin, Remzi; Dispinar, Derya; Tiryakioglu, Murat
    The effect of melt quality on hot tearing susceptibility of Al8Si3Cu alloy was examined under six different conditions, by using a traditional T-shaped mold. Grain refinement was carried out by two different modifiers: AlTi5B1 and Al3B. For each test, samples were cast before and after degassing of melt. Therefore, a new hot tearing tendency index was developed by both bifilm calculations and porosity that occurred in the middle of T-zone of casting parts. Results indicated that hot tearing of cast aluminum alloys was a complex phenomenon, and bifilms play a major role, especially by compensating for shrinkage and consequently contributing to the inconsistencies in results.
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    Freezing Range, Melt Quality, and Hot Tearing in Al-Si Alloys
    (Springer, 2018) Uludağ, Muhammet; Cetin, Remzi; Dispinar, Derya
    In this study, three different aluminum-silicon alloys (A356, A413, and A380) that have different solidification morphology and solidification ranges were examined with an aim to evaluate the hot tearing susceptibility. T-shape mold and Constrained Rod Casting (CRC) mold were used for the characterization. Reduced Pressure Test (RPT) was used to quantify the casting quality by measuring bifilm index. It was found that bifilm index and solidification range have an important role on the hot tearing formation. As it is known, bifilms can cause porosity and in this case, it was shown that porosity formed by bifilms decreased hot tearing tendency. As the freezing range of alloy increases, bifilms find the time to unravel that reduces hot tearing. However, for eutectic alloy (A413), due to zero freezing range, regardless of bifilm content, hot tearing was never observed. A380.1 alloy had the highest tendency for hot tearing due to having the highest freezing range among the alloys investigated in this work.
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    ON THE INTERPRETATION OF MELT QUALITY ASSESSMENT OF A356 ALUMINUM ALLOY BY THE REDUCED PRESSURE TEST: THE BIFILM INDEX AND ITS PHYSICAL MEANING
    (Springer International Publishing Ag, 2018) Uludağ, Muhammet; Cetin, Remzi; Dispinar, Derya; Tiryakioglu, Murat
    The oxide layer on liquid aluminum serves as a protective property to prevent the alloy from further oxidation. However, it has the potential to be a source of porosity when entrained into the bulk of the liquid. For this reason, oxides entrained into aluminum castings have been shown to degrade casting quality. In the current study, the effectiveness of the reduced pressure test in assessing the quality of A356 alloy melts has been investigated under various conditions obtained by changing six different melt parameters. Several metrics, including average pore size, number density of pores, bifilm index, have been used to measure melt quality. Results have shown that the bifilm index provides reliable measurements of melt quality. Moreover, the bifilm index has been found to have a physical meaning, volume fraction of pores, especially when bifilm index is higher than 50 mm.
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    Relationship Between Machinability, Microstructure, and Mechanical Properties of Al-7Si Alloy
    (Amer Soc Testing Materials, 2018) Uludağ, Muhammet; Yazman, Sakir; Gemi, Lokman; Bakircioglu, Baris; Erzi, Eray; Dispinar, Derya
    In this work, commercially available Al-7Si alloy was used, and the microstructure was modified by the additions of AlSr15, AlTi5B1, and Al3B. Cylindrical samples were cast into a sand mold and the machinability of the alloys was characterized by means of surface roughness, chip morphology, and buildup edge of the chips. Tool life and surface finish can be improved by decreased chip size by lowering the energy required for machining. The surface finish is an indicator of the quality of the material during the machining process. Therefore, in addition, melt quality was measured by means of reduced pressure test and the calculation of the bifilm index was used to compare the melt quality with machinability. It was found that there is a good correlation between bifilm index and surface roughness of the machined parts. Thus, for a better surface finish, melt quality, which can be quantified by bifilm index, has to be high. AlSr15 modified alloy exhibits the lowest built-up edge with the lowest surface roughness, because strontium modification causes coarse silicon crystals to transform to fine fibrous structure, which enhances machinability.
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    STATISTICAL ANALYSIS ON THE EFFECT OF THE SOLIDIFICATION RATE AND QUENCHING MEDIUMS ON MECHANICAL PROPERTIES IN ETIAL 221 ALLOY
    (2020) Uludağ, Muhammet; Gemı, Lokman; Dispinar, Derya
    In this study, the effects of different mold types and quenching mediums with different internal stresses on the mechanical properties of ETIAL 221 alloy supplied as a primer were investigated, and analyzed statistically. Firstly, the alloy was poured into the permanent mold (PM) then poured into sand mold with grain size 40/45 and 60/65 AFS. The specimens were subjected to three different T6 heat treatment quenching mediums that are water at room temperature (WRT), oil (OL) and boiling water (BW). The influences of differences in solidification rate due to cooling rates and differences in internal stress due to quenching mediums on mechanical properties were investigated. Additionally, the change in porosity was calculated according to Archimedes principle and obtained results were related to the mechanical properties. The results showed that permanent mold and boiling water quenching medium presented the best mechanical properties for the current study.
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    Statistical Distribution of Si Phases at Different Sr Levels in AlSi9 Alloys
    (Springernature, 2024) Kalkan, Ibrahim Halil; Hizli, Ibrahim Goksel; Dizdar, Kerem Can; Kahruman, Cem; Dispinar, Derya
    Al-Si alloys are widely used in many automotive applications. Mechanical properties of this alloy group strongly depend on the size, shape, and distribution of silicon phase. Therefore, Sr is added to alloy to alter the needle-like shape to fibrous morphology in order to achieve higher fluidity, increase feedability, decreased porosity, and high mechanical properties. In this work, the effect of strontium modification on the AlSi(9 )casting alloy were studied in detail. From 0 to 600 ppm, strontium was added to AlSi9 casting alloy and microstructural changes were evaluated. Metallographic characterization carried out on each sample and size and distribution of Si phase was analyzed by image analysis tools. Texture and pore figures were analyzed by EBSD.
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    The effects of degassing, grain refinement & Sr-addition on melt quality-hot tear sensitivity relationships in cast A380 aluminum alloy
    (Pergamon-Elsevier Science Ltd, 2018) Uludağ, Muhammet; Cetin, Remzi; Dispinar, Derya; Tiryakioglu, Murat
    Hot tearing tendency of A380 with various element additions (Sr, Sr + Ti, Ti, B and B + Sr) was investigated. Constrained rod casting (CRC) hot tearing test method was used to characterize the hot tearing sensitivity. Reduced pressure test (RPT) samples were produced from each condition and all trials were repeated three times. Number density of pores on the cross section of RPT samples was calculated via digital image processing and statistical analysis was carried out. Microstructure analysis was carried out to observe the effect of alloying elements. Hot torn cross sections were subjected to SEM analysis. It was found that in aluminum alloys, the most deleterious defects, bifilms that are the cause of many defects, play an important role in initiating the hot tearing during solidification. It is important to note that the shape, size and distribution of bifilms are too complex. They act as heterogeneous nucleation site for liquid to separate and thus increase hot tearing.