https://hdl.handle.net/20.500.12809/214 Sun, 19 Apr 2026 09:55:22 GMT 2026-04-19T09:55:22Z https://hdl.handle.net/20.500.12809/11044 Investigations of the Friction and Wear Resistance of the Natural Fiber-Reinforced Polyamide Composites Doğru, Alperen; Can Kaymaz, İbrahim; Kandemir, Miray Batikan; Seydibeyoğlu, Mehmet Özgür The search for natural and biobased materials to create a sustainable future has led many scientists to conduct research on natural-fiber-reinforced composites. Natural fibers have been used for thousands of years, but in the recent decades, they have been used in polymer composites as a reinforcement and/or filler. Natural fibers provide abundant resource in various countries through many forms. The use of natural fiber for structural composites is important in creating important new uses. Biobased materials are becoming more prominent in various applications including automotive parts and many other machinery. For the mechanical parts, friction and wear has been one of the most important topics for long-term performance of these products. In this book chapter, summary of natural fibers and their applications in polyamide composites has been well documented. The use of these composites has been investigated in terms of friction and wear properties. The wear and friction topics are commonly less studied in academic area, but they have a very significant importance for the industry. It is expected that this chapter will highlight the industrial use of these materials for long-term uses. Sun, 01 Jan 2023 00:00:00 GMT https://hdl.handle.net/20.500.12809/11044 2023-01-01T00:00:00Z https://hdl.handle.net/20.500.12809/10993 Magnetic properties of the FCC and BCC phases of (MnFeCoNi)(80)Cu(20_x)Z(x()Z(1)& nbsp;Al, Ga) high-entropy alloys Orbay, Yaşar; Rao, Ziyuan; Çakır, Aslı; Tavşanoğlu, Tolga; Farle, Michael; Acet, Mehmet In this work, the FCC-BCC phase transition in (MnFeCoNi)80Cu20 (Al, Ga) high entropy alloys were investigated on the basis of structural, magnetic, hardness and thermal expansion properties. It is found that the equiatomic MnFeCoNiCu alloy is FCC and exhibits mixed ferromagnetic/anti-ferromagnetic interactions with a Curie temperature, , close to room temperature. However, the BCC structure emerges with increasing amount of Al (10 at%) and Ga (15 at%) with additional ferromagnetic interactions and associated. It is evidenced that in terms of the valence electron concentration and the average magnetic moment values, the investigated HEAs obey the Slater-Pauling rule in a region close to the Heusler alloys. Additionally, they may exhibit similar physical properties like Invar property with low thermal expansion coefficient with the 3d-transition metal-alloys having same valence electron concentration. Sun, 01 Jan 2023 00:00:00 GMT https://hdl.handle.net/20.500.12809/10993 2023-01-01T00:00:00Z https://hdl.handle.net/20.500.12809/10966 Effect of different hydrogen Fugacities on the microstructure of additively manufactured Ti-6Al-4V Kaya, Ali Arslan; Metalnikov, Polina; Ben-Hamu, Guy; Eliezer, Dan In this study we compared the microstructural changes in the presence of hydrogen of Ti-6Al-4V alloy prepared by two different additive manufacturing (AM) methods: electron beam melting (EBM) and selective laser melting (SLM). Cathodic hydrogenation of AM Ti-6Al-4V resulted in significant expansion of β Ti phases due to the solute hydrogen, increasing of micro-strains, and α → titanium hydride/βH transformation. It was shown that SLM Ti-6Al-4V with acicular martensitic structure is more prone to hydrogen-induced phase transformation and hydrogen-assisted damage, compared to EBM. Moreover, it was revealed that different hydrogen charging environments cause different microstructural changes in EBM Ti-6Al-4V. Unlike cathodic hydrogen charging, gaseous hydrogen charging at elevated temperature reduced the process-induced micro-strains and promoted Al redistribution within the EBM Ti-6Al-4V. This resulted in massive precipitation of brittle α2-Ti3Al intermetallic compound, which act as a strong hydrogen trapping site aside from the Ti hydride phase. Sun, 01 Jan 2023 00:00:00 GMT https://hdl.handle.net/20.500.12809/10966 2023-01-01T00:00:00Z https://hdl.handle.net/20.500.12809/10957 Thermal plasma synthesis of (La,Sr)CoO3-(La,Sr)2CoO4 composite cathodes for intermediate temperature solid oxide fuel cells (IT-SOFC) Aysal, Havva Eda; Kılıç, Fahrettin; Çakmak, Gülhan; Öztürk, Tayfur (La,Sr)CoO3 and (La,Sr)2CoO4 dual phase powders were synthesized via thermal plasma to be used as cathodes for intermediate temperature solid oxide fuel cells (IT-SOFC). This covered pure (La,Sr)CoO3 as well as the composites where the fraction of (La,Sr)2CoO4 was gradually increased reaching the mid-composition. Powders, all synthesized in the same condition, were extremely small in size, especially at mid-composition where they were close to 30 nm in size. Area specific resistance (ASR) determined from the symmetric cell imply improved cathodic performance at the mid-composition. Taking ASR = 0.15 Ω∗cm2 as benchmark, it was found that the (La,Sr)CoO3: (La,Sr)2CoO4 = 0.53:0.47 cathode may be used at temperatures close 750 °C. Measurements taken from several runs however imply that the cathode performance was not stable and ASR values increases with cycling. This was attributed to the powder form of the cathode which would be expected to coarsen rapidly due to accelerated surface diffusion. Sun, 01 Jan 2023 00:00:00 GMT https://hdl.handle.net/20.500.12809/10957 2023-01-01T00:00:00Z