Browsing by Author "Ada, H."

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AISI 304L ÖSTENİTİK PASLANMAZ ÇELİKLERİN LAZER KAYNAĞIYLA BİRLEŞTİRİLMESİNDE NİTRASYON İŞLEMİNİN MİKROYAPI VE MEKANİK ÖZELLİKLERE ETKİSİNİN ARAŞTIRILMASI
(2023) Çoban, M.; Ada, H.; Çetinkaya, C.
Bu çalışmada; paslanmaz çeliklerin lazer kaynağıyla birleştirilmesi ve nitrasyon işleminin lazer kaynağına etkileri araştırılmıştır. Lazer kaynak yöntemiyle, 3 farklı güç parametresinde birleştirilen AISI 304L östenitik paslanmaz çelik numunelere uygulanan mekanik testlerde optimum sonuçların 1500 Watt güç ile birleştirilmiş 2. numunede olduğu görülmüştür. Mikroyapı ve mekanik özellikler açısından optimum sonucu veren 2 numaralı birleştirmeye ait parametreler baz alınarak kaynak öncesi ve sonrasında nitrasyon işlemlerinin uygulandığı 4 ve 5 numaralı deneyler gerçekleştirilmiştir. İncelemeler neticesinde kaynaklanan tüm numunelerde kaynak nüfuziyetinin yeterli olduğu, kaynaklı birleştirmenin penetrasyonunun uygun olduğu, ana malzeme mikroyapılarının eş taneli östenitik paslanmaz çelik mikroyapısına benzediği, kaynak metalinde kaynak merkezine doğru yönlenen dendritik ve sütünsal yapıların oluştuğu, ITAB’ın ise lazer kaynağının karakteristik özelliği olarak dar bir bölgede oluştuğu tespit edilmiştir. Optimum parametrede kaynak ve nitrasyon işlemleri gerçekleştirilen numunelerin mukavemet ve uzama değerleri 2 numaralı deneye yakın değerler gösterse de en yüksek çekme testi sonuçları 2 numaralı deneyde tespit edilmiş, tüm kopmalar ITAB bölgesinde meydana gelmiştir. Eğme testleri sonucunda; kaynaklı birleştirmelerin numunelerin sünekliğine tesir edecek herhangi bir olumsuzluk içermediği, ana malzemeye benzer süneklik sergilediği anlaşılmıştır. Mikrosertlik incelemelerinde; en yüksek mikrosertlik sonuçlarının ITAB bölgelerinde olduğu sonucuna varılmıştır.
An Examination of Microstructure, Microhardness and Tribological Properties of Ceramic Reinforced Bronze Matrix Composite Materials
(2023.01.01) Ada, H.; Türkmen, E.; Kaplan, Y.; Özcatalbas, E.; Satir, E.Y.; Aksöz, S.
In order to obtain better mechanical properties in a bronze alloy, it is important to produce new materials by adding reinforcements and to offer these materials to the industry. In this study, bronze matrix (Cu10Sn) materials were reinforced with boron carbide (B4C) and silicon carbide (SiC) ceramic materials by using the mechanical alloying method. New composite materials were produced by powder metallurgy method by adding ceramic reinforcement (B4C and SiC) at 1, 2, 4 and 8 weight ratios to Cu10Sn alloy, which is the main matrix material. The obtained composite materials examined in terms of structural, microhardness and wear resistance. Coefficient friction, specific wear rate and volume loss rates under 5N, 10N, and 15N loads were examined for the samples produced. When the applied microhardness and wear behaviors were examined, it was generally seen that the hardness and wear behaviors were improved with the added reinforcement ratios. In line with the examinations made, based on the hardness and wear processes applied to the materials consisting of the bronze matrix of the reinforcement material, it was observed that the most appropriate results were obtained from composite materials (Alloy 4 and Alloy 8), which contain 4% B4C and SiC reinforcement.
Evolution of fundamental mechanical properties with aliovalent Co/Cu partial substitution and preparation method for Y-123 system
(2024.01.01) Ozturk, O.; Safran, S.; Ada, H.; Bulut, F.; Seydioglu, T.; Nefrow, A.R.A.; Akkurt, B.; Terzioglu, C.; Yildirim, G.
This study investigates the effect of aliovalent Co/Cu replacement and preparation method on fundamental mechanical performance features of YBa2Cu3-xCoxO7-delta (Y-123) ceramic system depending on the crack propagation mechanism by Vickers hardness measurements (H-v) and mechanical investigation models for the first time. All the findings are verified by the scanning electron microscopy (SEM) examinations. Besides, the electron-dispersive X-ray (EDX) technique verifies the successful substitution mechanism. Besides, the Vickers hardness parameters improve systematically with the increment in the Co/Cu partial substitution (serving as a barrier) level due to formation of operable slip systems, ionic bond formations, and decrement of stress-amplified strain fields. Moreover, the Y-123 ceramic produced by solid-state reaction method and molecular weight of 0.20% presents the densest and smoothest surface morphology with the largest particle distributions and well-linked cobblestone-like grains. On the other hand, the Y-123 ceramic compounds produced by the sol-gel method are more sensitive and responsive to the indentation test loads. All the findings are wholly supported by the mechanical performance properties, including the shear modulus, resilience, and degree of granularity. Furthermore, the mechanical models indicate that every compound prepared exhibits the untypical reverse indentation size effect (RISE). Additionally, the modeling studies display that the induced cracking (IIC) approach is found to be the most appropriate method to examine true Vickers hardness parameters in the plateau limit regions. All in all, this comprehensive study reports efficiently exploiting the process-structure-property relationships in Y-123 ceramic material design for physical science and mechanical application fields using the aliovalent partial substitution and preparation condition.
Evolution of fundamental mechanical properties with aliovalent Co/Cu partial substitution and preparation method for Y-123 system
(Springer, 2024) Ozturk, O.; Safran, S.; Ada, H.; Bulut, F.; Seydioglu, T.; Nefrow, A.R.A.; Akkurt, B.; Terzioglu, C.; Yildirim, G.
This study investigates the effect of aliovalent Co/Cu replacement and preparation method on fundamental mechanical performance features of YBa2Cu3−xCoxO7−δ (Y-123) ceramic system depending on the crack propagation mechanism by Vickers hardness measurements (Hv) and mechanical investigation models for the first time. All the findings are verified by the scanning electron microscopy (SEM) examinations. Besides, the electron-dispersive X-ray (EDX) technique verifies the successful substitution mechanism. Besides, the Vickers hardness parameters improve systematically with the increment in the Co/Cu partial substitution (serving as a barrier) level due to formation of operable slip systems, ionic bond formations, and decrement of stress-amplified strain fields. Moreover, the Y-123 ceramic produced by solid-state reaction method and molecular weight of 0.20% presents the densest and smoothest surface morphology with the largest particle distributions and well-linked cobblestone-like grains. On the other hand, the Y-123 ceramic compounds produced by the sol–gel method are more sensitive and responsive to the indentation test loads. All the findings are wholly supported by the mechanical performance properties, including the shear modulus, resilience, and degree of granularity. Furthermore, the mechanical models indicate that every compound prepared exhibits the untypical reverse indentation size effect (RISE). Additionally, the modeling studies display that the induced cracking (IIC) approach is found to be the most appropriate method to examine true Vickers hardness parameters in the plateau limit regions. All in all, this comprehensive study reports efficiently exploiting the process–structure–property relationships in Y-123 ceramic material design for physical science and mechanical application fields using the aliovalent partial substitution and preparation condition.