Browsing by Author "Islak, S."

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Effect of boron on microstructure, thermal, and mechanical properties of Ni-B matrix diamond cutting tools
(2024.01.01) Islak, S.; Celik, E.; Houssain, H.; Danaci, H.C.
This study examines the impact of adding boron on the microstructural, thermal, and mechanical properties of Ni-B alloy matrix diamond cutting segments, which are created using the hot pressing process. Microstructure was investigated using SEM-EDS and XRD analysis. The high-temperature oxidation behavior of the samples was determined by thermogravimetric analysis. The hardness was quantified employing Vickers hardness testing, as well as, sample densities were derived based on Archimedes' principle. The wear resistance was evaluated using the reciprocating wear test method. A three-point bending test was used to examine how the diamond grains were retained inside the Ni-B matrix. The XRD investigations identified the formation of Ni, Ni3B, and Ni2B phases. The thermogravimetric analysis results showed that Ni-B alloys were exposed to oxidation at elevated temperatures as the B content increased, However, a hardness improvement was observed as the B content increased due to the formation of borides. Furthermore, the tribological investigation reveals that adding the B as reinforcement has a positive effect at a specific amount, where the optimal wear resistance and minimal friction coefficient were evident at 6% B contained sample.
Microstructural, mechanical, and biocompatibility properties of Ti-Cu/B4C composites for biomedical applications
(2024.01.01) Islak, S.; Houssain, H.; Emin, N.; Yazar, H.; Danaci, H.C.; Koç, V.
This study investigated the effects of B4C on the microstructural, mechanical, and biocompatibility properties of Ti-Cu/B4C composites produced by powder metallurgy. Different amounts of B4C (3, 6, 9, and 12 %) were added to the Ti-Cu matrix. XRD results showed that Ti2Cu, alpha-Ti, TiB, and B4C phases formed in the microstructure. The addition of B4C and the phases forming in the microstructure resulted in significant increases in the hardness and wear resistance of the composites. SEM images of the wear surfaces showed that the abrasive wear mechanism was dominant. Biodegradability analyses showed that sodium, found in trace amounts in the structure of the alloys, and calcium, released from the structure of B4C into the medium, were the least at the addition of 6 % B4C. Considering the reduced amount of phosphate in the medium, it was found that the mass gain observed in the specimens was due to the deposition of calcium-phosphate precipitates on the surface of the composites. This result suggested that Ti-Cu/B4C alloys were bioactive for bone and may provide osteointegration. Indirect MTT analysis with bone marrow mesenchymal stem cells showed that the specimens were cytotoxic at an acute dose on the first day. However, the cytotoxic effect diminished when they were kept in the PBS medium and replaced every other day for 28 days. Notably, the composite specimen with the addition of 6 % B4C demonstrated maximum cytocompatibility. Consequently, it indicated that adding B4C to the alloy improved osteogenic properties, although it partially increased copper release into the medium.
Microstructural, mechanical, and biocompatibility properties of Ti–Cu/B4C composites for biomedical applications
(Elsevier Ltd, 2024) Islak, S.; Houssain, H.; Emin, N.; Yazar, H.; Danacı, H.C.; Koç, V.
This study investigated the effects of B4C on the microstructural, mechanical, and biocompatibility properties of Ti–Cu/B4C composites produced by powder metallurgy. Different amounts of B4C (3, 6, 9, and 12 %) were added to the Ti–Cu matrix. XRD results showed that Ti2Cu, α-Ti, TiB, and B4C phases formed in the microstructure. The addition of B4C and the phases forming in the microstructure resulted in significant increases in the hardness and wear resistance of the composites. SEM images of the wear surfaces showed that the abrasive wear mechanism was dominant. Biodegradability analyses showed that sodium, found in trace amounts in the structure of the alloys, and calcium, released from the structure of B4C into the medium, were the least at the addition of 6 % B4C. Considering the reduced amount of phosphate in the medium, it was found that the mass gain observed in the specimens was due to the deposition of calcium-phosphate precipitates on the surface of the composites. This result suggested that Ti–Cu/B4C alloys were bioactive for bone and may provide osteointegration. Indirect MTT analysis with bone marrow mesenchymal stem cells showed that the specimens were cytotoxic at an acute dose on the first day. However, the cytotoxic effect diminished when they were kept in the PBS medium and replaced every other day for 28 days. Notably, the composite specimen with the addition of 6 % B4C demonstrated maximum cytocompatibility. Consequently, it indicated that adding B4C to the alloy improved osteogenic properties, although it partially increased copper release into the medium.
Microstructure, mechanical, and cutting performance properties of B4C and SiC reinforced sandwich composite segments
(Elsevier Ltd, 2024) Islak, S.; Çelik, E.; Erol, M.; Houssain, H.
This study aims to extend the work-life of diamond-cutting segments and to economize the operating cost of diamond-cutting tools. In order to achieve this object, bronze matrix sandwich segments reinforced with SiC and B4C were produced utilizing the hot pressing technique. In the term of the cutting segments, it is favorable that the outer layers are wear-resistant and the middle layer is tough. SEM and XRD analysis were used to determine the microstructural properties. Mechanical properties were evaluated by conducting hardness, wear, cutting performance, and three-point bending tests. The cutting performance of the segments was determined by turning andesite marble. SEM examinations showed that SiC and B4C grains were homogeneously distributed in the bronze matrix. The highest hardness value was 113.9 HB in the B4C reinforced sandwich segment. The reciprocating wear test findings indicated that the matrix exhibited the lowest wear rate in the B4C reinforced sandwich composite segment, followed by the hybrid sandwich composite segment. The lowest amount of cutting loss after turning andesite stone was achieved in the SiC, and B4C reinforced hybrid sandwich composite segment. The cutting performance of the hybrid sandwich composite segment increased by 46.15 % compared to the conventional segment without additives. The highest value of the transverse rupture strength of the specimens was 380 MPa for the B4C reinforced sandwich composite segment and 352 MPa for the hybrid sandwich composite segment. Considering all the tests and analyses, the hybrid sandwich composite segment sample may be the most suitable for diamond-cutting tools
Microstructure, wear and corrosion properties of Cu-SiC/WCCo composite coatings on the Cu substrate surface by plasma spray method
(2024.01.01) Özorak, C.; Islak, S.
In this study, the microstructure, wear and corrosion properties of Cu–SiC/WCCo composite coatings produced on Cu substrates by plasma spray method were investigated. In order to achieve this aim, SiC and WCCo powders were added to copper at different rates such as 5 %, 10 % and 20 % by weight. In order to determine the microstructure properties and phase distribution of the produced coatings, optical microscope, SEM-EDS and XRD analysis were investigated. The reciprocating wear method was used in order to determine the wear properties and the potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) methods was used to determine the corrosion properties. The electrical conductivities of the coating layers were performed according to the eddy current principle. XRD analysis results showed that in both coating types, ceramic particles decomposed in the plasma flame and as a result, binary and ternary metallographic phases were formed. There were significant increases in hardness by adding ceramic particles to Cu, especially with 20 % WCCo additive, the hardness obtained was 82 % higher than the Cu substrate. When the wear properties were examined, both abrasive/adhesive wear types were observed in the copper substrate and coating layers. In all samples, material loss increased as the load increased. Both EIS measurements and Tafel curve results showed that the Cu5% WCCo coating had the best corrosion resistance among the coatings. When the electrical conductivity results of all samples were compared, the electrical conductivity decreased with increasing rate of carbide in the coating.
The effect of SiC amount on microstructure and wear properties in SiC-reinforced Mo5SiB2
(2024.01.01) Islak, S.; Kriewah, OAE
This study aimed to investigate how silicon carbide (SiC) reinforcement affected the microstructure and wear properties of Mo5SiB2-based alloy fabricated by powder metallurgy. The main reasons for using SiC in this study are that it is affordable and improves the wear resistance of the Mo5SiB2-based alloy. SiC at 2 %, 4 %, and 6 % by volume was added to Mo5SiB2-based alloy. After cold pressing and sintering, the samples' microstructure, density, hardness, and wear properties were analyzed in detail. Scanning electron microscope (SEM) images indicated that a porous and skeletal structure formed as a microstructure. This structure became more pronounced with an increased SiC rate. X-ray diffraction (XRD) results showed that Mo5SiB2 (T2 phase), Mo3Si (A15 phase), alpha-Mo, SiO2, and SiC phases formed in the microstructure. With increasing SiC rate, the peaks of binary and ternary phases increased. The experimental densities dropped upon the reinforcement of SiC. The hardness of the samples reached the maximum value (1639HV2) in the Mo -Si -B alloy at 6 % SiC rate. The results of the pinon-disk wear tests run to assess the wear performance of the samples indicated that the best wear performance was achieved in the 6 % SiC-reinforced sample with a coefficient of friction (COF) of 0.49 and a wear rate of 0.43 x 10-5 mm3 (N.m)-1.
The effect of SiC amount on microstructure and wear properties in SiC-reinforced Mo5SiB2
(Elsevier Ltd, 2024) Islak, S.; Kriewah, O.A.E.
This study aimed to investigate how silicon carbide (SiC) reinforcement affected the microstructure and wear properties of Mo5SiB2-based alloy fabricated by powder metallurgy. The main reasons for using SiC in this study are that it is affordable and improves the wear resistance of the Mo5SiB2-based alloy. SiC at 2 %, 4 %, and 6 % by volume was added to Mo5SiB2-based alloy. After cold pressing and sintering, the samples' microstructure, density, hardness, and wear properties were analyzed in detail. Scanning electron microscope (SEM) images indicated that a porous and skeletal structure formed as a microstructure. This structure became more pronounced with an increased SiC rate. X-ray diffraction (XRD) results showed that Mo5SiB2 (T2 phase), Mo3Si (A15 phase), α-Mo, SiO2, and SiC phases formed in the microstructure. With increasing SiC rate, the peaks of binary and ternary phases increased. The experimental densities dropped upon the reinforcement of SiC. The hardness of the samples reached the maximum value (1639HV2) in the Mo-Si-B alloy at 6 % SiC rate. The results of the pin-on-disk wear tests run to assess the wear performance of the samples indicated that the best wear performance was achieved in the 6 % SiC-reinforced sample with a coefficient of friction (COF) of 0.49 and a wear rate of 0.43 × 10−5 mm3 (N.m)−1
TIG YÖNTEMİYLE 45Mn5 ÇELİK YÜZEYİNDE ÜRETİLEN SiC ESASLI KAPLAMALARIN MİKROYAPI KARAKTERİSTİKLERİ
(Proceedings of 11th International Materials Symposium, April 19-21, 2006, Denizli, Türkiye TÜBİTAK, 2006) Yıldırım, M. M.; Buytoz, S.; Islak, S.
Bu çalışmada, bir 45Mn5 çelik yüzeyinde tungsten asal gaz (TIG) yöntemiyle üretilen SiC esaslı kaplamaların, mikroyapı ve mikrosertliğine üretim parametrelerinin etkileri deneysel olarak incelenmiştir. Üretim parametrelerinin özellikle enerji girdisi ve toz miktarına bağlı olarak, farklı mikroyapılar elde edilmiştir. Düşük toz miktarlarında mikroyapıda dendritik bir katılaşma meydana gelmiştir. Yüksek toz miktarlarında ise, ötektik dönüşümün bir sonucu olarak birincil dendritlerle birlikte, M7C3, FeSi2 ve SiC oluşmuştur. Yapıdaki karbür ve fazların cinsine ve miktarlarına bağlı olarak kaplamaların sertlik değerleri de değişmiştir. Maksimum sertlik 1058 HV olarak 30.1 kJ/cm enerji girdisi ve 2.5 g toz miktarıyla üretilen numuneden elde edilmiştir. Bunun nedeni ise yapıdaki SiC ve M7C3 karbürlerinin varlığıyla ilişkilendirilmiştir.