Yayla, Nihal; Şimşek, Telem; Boyrazlı, Mustafa; Güler, Ömer

Neodymium (Nd), a rare earth element, was incorporated into the [FeCoNiCu(MnCr)0.5] high-entropy alloy (HEA) at weight percentages of 0.5%, 1%, 2%, and 5%. The alloys were synthesized successfully using the arc melting method. X-ray diffraction (XRD) analysis confirmed that both the undoped and Nd-doped alloys exhibit a single-phase solid solution with a face-centered cubic (FCC) crystal structure, consistent with thermodynamic predictions derived from the Miedema model. Scanning electron microscopy (SEM) revealed a dendritic structure in the undoped alloy, which was replaced by Cu- and Cr-rich regions in the 5% Nd-doped alloy, as confirmed by energy dispersive spectroscopy (EDS). Differential scanning calorimetry (DSC) indicated an endothermic peak in the undoped alloy and minor thermal responses in Nd-doped samples, without distinct phase transitions within the 0–800 °C range. Mechanical testing demonstrated substantial enhancements in both hardness and tensile strength with increasing Nd content. The 5% Nd-doped alloy exhibited the highest performance, achieving a Vickers hardness of 370 HV and a tensile strength of 1186 MPa. Magnetic testing indicated ferromagnetic behavior in all samples, with Nd additions significantly enhancing magnetic properties. Notably, the 5% Nd-doped alloy achieved a saturation magnetization (Ms) of 41 emu/g and a coercivity (Hc) of 6.3 Oe, highlighting improved magnetic softness and rapid magnetization loss characteristic of soft magnetic materials.

AtıfScopus2·WoS1·OpenAlex1

İncele

Güler, Ömer; Boyrazlı, Mustafa; Albayrak, Muhammet Gökhan; Güler, Seval Hale; Ishihara, Tatsumi; Edalati, Kaveh

One of the most promising solutions to slow down CO2 emissions is the use of photocatalysis to produce hydrogen as a clean fuel. However, the efficiency of the photocatalysts is not at the desired level, and they usually need precious metal co-catalysts for reactions. In this study, to achieve efficient photocatalytic hydrogen production, a high-entropy oxide was synthesized by a mechano-thermal method. The synthesized high-entropy oxide had a bandgap of 2.45 eV, which coincided with both UV and visible light regions. The material could successfully produce hydrogen from water under light, but the main difference to conventional photocatalysts was that the photocatalysis proceeded without a co-catalyst addition. Hydrogen production increased with increasing time, and at the end of the 3 h period, 134.76 µmol/m2 h of hydrogen was produced. These findings not only introduce a new method for producing high-entropy photocatalysts but also confirm the high potential of high-entropy photocatalysts for hydrogen production without the need for precious metal co-catalysts.

AtıfScopus33·WoS30

İncele

Başbağ, Güneş; Karaduman, Oktay; Canbay, Canan Aksu; Özkul, İskender; Boyrazlı, Mustafa

In this work, the new quaternary CuAlTiMg high-temperature shape memory alloy (HTSMA) with an unprecedented composition and with extended solubility of Ti was produced by the arc melting method. The thermal shape memory effect characterization tests were done by performing a series of differential calorimetric (DSC and DTA) measurements. The obtained thermograms of the alloy displayed the martensitic phase transformation peaks. The forward (martensite to austenite) phase transformation was found to occur at above 350◦C, which qualifies the produced alloy as an HTSMA. The microstructural XRD measurement was performed to reveal the atomic planes of martensite structures formed in the alloy, which constitute the shape memory effect property of the fabricated alloy. The alloy surface was monitored by optical microscopy image taken at room temperature, and finely dispersed Ti-rich X-phases were observed.

İncele