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- MakaleAçık Erişim2026Scopus SJRQ2Investigation of the Mechanical and Metallographic Effects of Adding 2-3% Al-Ti-Mo Elements to High-Entropy CoCrFeNi Alloys
Dilek, İlhan; Taşgın, Yahya; Kanca, Muhammed Sait; Kök, Mediha; Güler, Ömer
Recently, high-entropy alloys (HEAs) have attracted significant attention due to their unique multicomponent composition and exceptional mechanical properties, such as high wear and corrosion resistance, making them superior to conventional alloys for advanced engineering applications. The effects of Al, Ti, and Mo addition on the microstructural and mechanical properties of CoCrFeNi-based HEAs were investigated. The alloys were produced via powder metallurgy and vacuum arc melting, with the addition of 2 and 3% Al, Ti, and Mo, respectively. Scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDS), and x-ray diffraction (XRD) were used to perform microstructural characterization, while microhardness and wear tests were used to evaluate mechanical performance. The addition of Al and Ti enhanced the face-centered cubic phase stability and increased the hardness by improving the lattice structure. In contrast, the addition of Mo contributed to solid solution and precipitation hardening, resulting in a simpler microstructure and superior tribological performance. Among all compositions, the alloy with 3% Mo addition exhibited the highest hardness value (≈ 233.8 HV) and the lowest mass loss (4.3 mg) was observed, indicating a significant improvement in the wear resistance and mechanical strength. In conclusion, the addition of Ti and Mo to CoCrFeNi HEAs promotes solid solution, precipitation, and grain boundary hardening mechanisms, thereby enhancing microstructural integrity, hardness, and wear resistance. These findings suggest that such alloys are promising candidates for use as next-generation structural and tribological materials under demanding operational conditions.
- MakaleYalnız künye2024Scopus SJRQ2Production of CoCrFeNi(Al/Ti) High-Entropy Alloys by Mechanical Alloying: Optimization of Milling Time and Comparison of Corrosion Susceptibilities
Say, Yakup; Dikici, Burak; Kaseem, Mosab; Özkul, İskender; Güler, Ömer
CoCrFeNi alloy is the most well-known four-component equiatomic alloy. In addition, it has a low-cost composition among HEAs. Four-component alloys are considered semi-HEAs. Therefore, a five-component HEA design was made by adding another metal to the main composition of CoCrFeNi. As the fifth metal, two metals such as Al and Ti, which are relatively low in cost and have the potential to improve properties, were chosen. For this purpose, in this study, the effect of Al and Ti on CoCrFeNi main alloy was investigated by producing three different samples as CoCrFeNi, CoCrFeNiAl, and CoCrFeNiTi. The alloys with three different compositions (used three different samples) were successfully produced by the mechanical alloying method. Although Al and Ti have the possibility of intermetallic with other metals in the alloy, such a formation was not observed during mechanical alloying, and it was observed that all metals were homogeneously distributed in the alloy. The microhardness results indicated that CoCrFeNiAl and CoCrFeNiTi samples had similar hardness values. While the hardness of the CoCrFeNi sample was 136 HV, the hardness of the CoCrFeNiAl sample was 262 HV. However, the hardness of the CoCrFeNiTi sample decreased significantly. The hardness of the CoCrFeNiTi sample was measured as 269 HV. It was observed that the addition of Ti and Al to the base alloy was increased a significant change in hardness. It has been observed that Ti supplementation has a more positive effect on improving corrosion properties. It is seen that the corrosion potentials shift toward more negative potentials with the addition of Al and Ti to the CoCrFeNi (−194 mV) alloy (−306 and −224 mV for CoCrFeNiAl and CoCrFeNiTi, respectively). When the surface morphologies of the alloys are compared after corrosion; the damage to the alloy surfaces increases due to the negative Ecorr value in CoCrFeNiAl and CoCrFeNiTi alloys compared to the master alloy. However, the high corrosion current density (12.69 µA/cm2) in the CoCrFeNiTi sample caused much more damage to this alloy. Graphical Abstract: (Figure presented.)
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İncele - MakaleYalnız künye2023Scopus SJRQ2The Effect of Using Ferro-Alloy on the Properties of AlCoFeNiMoTi High-Entropy Alloy Produced by Arc-Melting Method: Design of Low Cost
Güler, Seval H.
The cost of high-entropy alloys (HEAs) is one of the most major obstacles to their widespread use. The cost of these alloys with significant amounts of five metals might reach very high levels depending on the type and quantity of metal utilised. Therefore, this study examined the effect of the use of ferro-alloys as part of the charge mixture on the properties of AlCoFeNiMoTi alloy. Ferro-alloys are much less expensive than the pure form of the same metal. To that end, two groups of samples were produced. The AlCoFeNiMoTi alloy was produced using high-purity metals as the metallic charge in the first group of samples. Instead of utilising the pure forms of some expensive metals that make up such alloy, as the metallic charge, lower-cost ferro-alloy forms were employed in the second group of samples. Following the preparation of the appropriate compositions, alloys were produced using the arc-melting method, and the produced alloys were subject to homogenization heat treatment. The obtained samples were characterised by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Then, mechanical and corrosion tests were run. The corrosion resistance of the HEAs was compared with an electrochemical polarisation technique in a 3.5% NaCl electrolyte. It was observed that many intermetallics precipitated through the heat treatment of the samples, and the precipitates negatively affected the mechanical properties of the alloy. Also, in the samples in which ferro-alloy was used instead of pure metal, the mechanical properties were substantially degraded. This is believed to be associated with the presence of inclusions and other residues in ferro-alloys. Graphical Abstract: [Figure not available: see fulltext.]
AtıfScopus6WoS7OpenAlex7İncele - MakaleYalnız künye2022Scopus SJRQ2Boron nitride nanosheet-reinforced WNiCoFeCr high-entropy alloys: the role of B4C on the structural, physical, mechanical, and radiological shielding properties
Kavaz, Esra; Gul, Ali Oktay; Basgoz, Oykum; Guler, Omer; ALMisned, Ghada; Bahceci, Ersin; Guler, Seval Hale; Tekin, H.O.
The synthesis and extensive characterization of newly developed boron nitride nanosheet (BNNSs)-reinforced WNiCoFeCr high-entropy alloys (HEAs) are presented. The influence of B4C on the structural, physical, mechanical, and nuclear shielding characteristics of synthesized HEAs has been widely examined in terms of its monotonic effects on the behavior changes. The internal morphology and structural characteristics of the fabricated composites are first investigated using X-ray diffraction, scanning electron microscopy, and energy-dispersive spectroscopy. Wear testing is used to determine the coefficient of friction as a function of sliding distance. Experimental gamma ray and neutron setups are created to determine their shielding characteristics against nuclear radiation. Finally, the shielding characteristics of nuclear radiation for gamma ray and fast neutrons are compared extensively to those of many existing and new-generation shielding materials. Among the examined samples, the S2 sample with B4C and BNNSs reinforcement had the greatest mechanical characteristics. Our findings imply that increasing B4C directly contributes to the shielding qualities of nuclear radiation. The B4C created in the structure of BNNSs contributes to the overall properties of HEAs, which are crucial for nuclear applications, since HEAs are being examined as a component of future nuclear reactors. Additionally, B4C is a very versatile material that may be used in circumstances where mechanical and nuclear shielding properties need to be enhanced for a variety of radiation energies.
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