This study explores the physical, structural, and radiation shielding enhancements in Inconel 718 superalloys reinforced with 1 wt% Y2O3 and varying Pr2O3 contents from 0 to 10 wt%, respectively. X-ray diffraction analysis confirmed preservation of the face-centered cubic structure, with increasing Pr2O3 inducing peak broadening and partial amorphization. The scanning electron microscopy/energy-dispersive X-ray spectroscopy results verified the homogeneous dispersion of oxides without agglomeration. Gamma-ray shielding parameters, including the mass attenuation coefficient (MAC), half-value layer, and effective atomic number, significantly improved with higher Pr2O3 content, particularly at low to mid photon energies.The 718Y-10PO sample exhibited the lowest transmission factors and the highest MAC values across all the tested energies. Buildup factors decreased in the Pr-rich samples, confirming reduced photon scattering. Notably, the fast neutron removal cross section for 718Y-10PO as 0.15521 cm-1 exceeded the benchmark materials like graphite and B4C. These findings establish the 718Y-10PO alloy as a promising candidate for advanced nuclear shielding applications, combining structural integrity with promising gamma and neutron attenuation capabilities.

In this study, a novel FeCoNiMnCu HEA was synthesized via mechanical alloying and exhibited a single-phase face-centered cubic (FCC) structure with a crystallite size of 11.7 nm and a lattice strain of 0.81 %. Magnetic characterization revealed soft ferromagnetic behavior with a saturation magnetization of 32 emu/g at 300 K, increasing to 53 emu/g at 10 K. The alloy demonstrated excellent gamma-ray attenuation, with lower half-value layer (HVL) and mean free path (MFP) values than conventional shielding materials. Notably, its fast neutron removal cross-section (Sigma R = 0.1654 cm- 1) outperformed standard materials such as B4C, graphite, and water in the fast neutron energy range. These findings underline the multifunctional performance of FeCoNiMnCu HEA, highlighting its strong potential for use in advanced nuclear reactor components and radiation shielding technologies.

Wear in moving materials in contact with each other is an inevitable cause of damage. To prevent this damage, various processes are applied to the material surfaces. The most widely used method is the surface hardening method. This study aims to examine the wear properties of the samples by forming a hard boride layer on the surface of low-carbon steel such as St28 with experimental and artificial intelligence approaches. In this context, it is aimed to obtain the boride layer at relatively low temperatures by pre-processing the powder mixture to be used as a boron source, such as Mechanical Alloying (MA). The boronizing process was carried out using the box boronizing technique. The wear behavior of the obtained samples was investigated by the block-on-disk method. In artificial intelligence approaches; The dataset is divided into three categories as 10N, 20N, and 40N. There are 39 sample types and attributes in each category. In this study, feature selection algorithms such as linear regression (LR), ridge, recursive feature elimination (RFE), f-regression, and multiple inclusion criterion (MIC) were used to select the most efficient samples. Then the best samples were classified according to their force types. Ensemble learning methods, machine learning methods, and Bayesian neural networks were used in the classification processes. Thanks to the proposed approach and feature selection algorithm, the best performance has been shown up to 10 feature selection. By ignoring 29 inefficient features, classification was performed with 10 efficient features. In the classification process, 100% overall accuracy was achieved.

Abstract In this study, the effect of mechanical alloying on the growth kinetics of boride layer of boronized DIN St28 steel surface was investigated. The powders containing B + SiC + KBF4 were mechanically alloyed by planetary ball milling devices to 10 and 20 h, respectively. The samples were also boronized by the powder-(SiO2–Na2O) mixture for 1023–1173 K temperature and 3, 6 and 12 h, respectively. At the end of the mechanical alloying process, it was determined that the powder particle sizes were in the nanometer scale. According to the microstructure analysis, a single-layer Fe2B structure was successfully obtained on the samples surfaces. It has been observed that the depth of the Fe2B boride layer, which has achieved high diffusivity by creating many defects in the form of nanometer-sized crystal particles, increased with repeated fracture and cold welding of the powder particles with increasing mechanical alloying times. By calculating the activation energies of the powders, their relations with the mechanically unalloyed samples were compared and empirical formulas that could be used for similar experimental conditions were produced.

Surface coating processes are carried out at high temperatures, so high heat input is applied to the material to be coated and may cause internal structure deterioration. In order to overcome this situation, the ability to reduce the coating temperature with a pretreatment such as Mechanical Activation was investigated in this study. In order to minimize the effect of alloying elements, DIN St28 steel is used. Powders containing B + SiC + KBF 4 were mechanically alloyed by planetary ball milling devices to 10 and 20 h, respectively. By mixing boron-containing powder and sodium silicate, the samples were boronized at 923-1173 K temperature and 3-12 h. At the end of the mechanical alloying process, it was determined that the powder particle sizes were in the nanometer scale. According to the microstructure analysis, a single-layer Fe 2 B structure was successfully obtained on the samples surfaces. While no boride layers were formed on the sample surfaces at temperatures below 1023 K without MA pretreatment, boride layers were formed under these temperatures with MA pre-treatment. It has been observed that the depth of the Fe 2 B boride layer, which has achieved high diffusivity by creating many defects in the form of nanometer-sized crystal particles, increased with repeated fracture and cold welding of the powder particles with increasing mechanical alloying times. By calculating the activation energies of the powders, their relations with the mechanically unalloyed samples were compared and empirical formulas that could be used for similar experimental conditions were produced. The highest microhardness value was measured as 2200 HV and above.

In this study, Fe 2 O 3 , TiO 2 , and CdO semiconductor metal oxides were separately incorporated into the ZnO-MWCNT composite at different weight percentages. Accordingly, several experimental analyses on electrical, optical, and radiation shielding characteristics of coupled semiconductor metal oxides nanocomposites were performed to determine their monotonic impact on the investigated material properties. Moreover, gamma-ray shielding properties of these novel materials were determined using MCNPX general-purpose Monte Carlo code. At 5% oxide addition, the maximum electrical conductivity was found in all groups for all temperatures. Moreover, 5% oxide reinforcement resulted in the maximum reflection characteristics in all groups. Among the CdO doped materials, the CZnOCd5 sample exhibits the highest electrical conductivity behaviour at room and high temperatures. The Eg value calculated for the CZnOCd5 sample was 3.284 eV. The CZnOCd2.5 and CZnOCd5 samples had the greatest Eg values when compared to the pure sample and the samples from other groups. The CZnOCd5 sample has the highest reflectance value in the CZnOCd group's reflectance graph. On the other hand, the maximum gamma-ray attenuation properties were reported for CZnOCd5 sample. Among the analysed samples, the CZnOCd5 sample's characteristics provide a preliminary motivation for a more comprehensive analysis of this material and assessment of potential radiation protection applications.

Carbon nanotubes (CNTs) have been used as reinforcing material for many different matrices. There are many studies in the literature reporting that reinforcement of CNTs into concrete matrix improved the properties of the concrete. In this study, first unmodified CNTs were reinforced to concrete and it was seen that there were partial decreases in strength despite the increasing rate of CNTs. Thereon, the surfaces of CNTs to be used as reinforcing material were modified with water-soluble surfactants (Polyvinyl alcohol-PVA, Polyvinylpyrrolidone-PVP, Poly (ethylene glycol)-PEG, Dodecylamine-DDA) and reinforced with concrete. In previous studies, many different surfactants were tried to functionalise the surfaces of CNTs. However, in this study, water-soluble polymeric surfactants were preferred without the need for an additional process in order to modify the surfaces of CNTs. In addition, the effect of the surfactants used on the mechanical properties of concrete was examined comparatively. Although the amount of CNTs reinforcement is very low like 0.05 wt%, the increase in strength was seen to be above 60%. The highest strength values were obtained in the sample in which PVA was used as surfactant. Through the surfactants used, bundles of CNTs were fully opened and distributed homogeneously into the concrete matrix, and all of the CNTs were embedded into the matrix by getting wet by the matrix. In the real application, it will be possible to use new generation concretes with higher strength and lighter weight by providing the ease of reinforcing CNTs to the concrete matrix.

In this study, titanium dioxide (TiO2)-based graphene nanoplatelets (GNPs)-reinforced composite materials were produced and the electrical and optical properties of the composite materials were investigated. Graphene, which was used as a reinforcing material, was produced by using liquid-phase exfoliation method. While the TiO2 used as matrix material was commercially available for the first group of samples, it was produced by using the sol–gel method for the second group of the samples. Different rates of graphene were added to the TiO2 powders which were commercially available and produced by using sol–gel method. GNPs used as a reinforcing material were subjected to TEM analysis. The resulting composite materials were structurally examined in SEM and XRD. Then, the changes in electrical conductivity of these composites under the impact of temperature were measured. UV–Vis spectrometers of the samples were taken and their optical properties were determined. When temperature-based electrical examination of the produced composite materials was performed, an increase was observed on the electrical conductivity values in both groups of samples as a result of addition of the reinforcing element. In addition, TiO2-containing composites produced by using sol–gel method had lower electrical conductivity comparing with commercially purchased TiO2-containing composites especially at high temperatures. In the optical measurements, it was observed that there was an increase in the optical bandgap energy range values with GNPs reinforcement but a decrease in the reflectance values.

Even though high quality graphene can be produced through chemical exfoliation of Graphite or Expanded graphite (EG), the amount of acquired products is limited. Graphite powders were subjected to a pre-milling process with prevailing shear stress in order to increase the amount of products. Therefore, separation of hexagonal layers through pre-separation process was targeted. The milled powders were firstly mixed in the saturated acid mixture containing H2SO4 and HNO3, and then heated to 950 degrees C. At the end of process, the distance between layers was expanded and the structure called as expanded graphite was obtained. Separation of layers and formation of graphene were provided by stirring expanded graphite within a chemical solvent for a while. The obtained samples were examined by using X-ray analysis, electron microscopy analysis, and Raman spectroscopy analysis. Despite the fact that there is a production method for graphene by chemical exfoliation, addition of the milling into steps of this process is an unusual step. Although a great amount of amorphous structures occurred in the structure at the end of milling process in this study, there were still graphitic structures preserving its hexagonality in the sample even if just a little. Most of amorphous carbon was removed from the structure as a result of applying further steps of process to milled graphite. A great part of graphitic structures apart from amorphous carbon structures were transformed into graphene. Even though amorphous carbon structures and defects were still found in the product, the obtained graphenes were relatively qualified and of high amount.

Bu calismada karbon nanotup takviyeli titanyum oksit (anataz) esasli kompozit malzemeye degisen miktarlarda rutil fazina sahip titanyum oksit etkisi incelenmistir ve elde edilen numunelerin elektriksel ve optik ozellikleri incelenmistir. Karbon nanotupler bir altlik kullanilarak kimyasal buhar cokturme yontemi ile sentezlenmistir. Daha sonra, elde edilen nanotupler ticari olarak temin edilen titanyum oksit (anataz) icerisine agirlikca % 0.5 oraninda takviye edilmistir. Elde edilen bu numunelere % 5, 10, 15 ve 20 oranlarinda rutil fazi eklenmistir. Sentezlenen karbon nanotupler TEM’de incelenmistir. Elde edilen nanotuplerin yapisal analizi XRD incelemesi ile yapilmistir. Son olarak elde edilen kompozitler SEM altinda incelenmis, sicakliga bagli elektriksel iletkenligi incelenmis ve UV-vis spektrometresi kullanilarak optik ozellikleri tespit edilmistir.

Multi-layer graphene was produced through synthesized expanded graphite (EG) liquid exfoliation using organic solvent. Hexagonal graphite (HG) was used as a starting material. HG was mixed with an acidic mixture, dried, rand subjected to thermal treatment. After this process, EG was obtained. This obtained EG was sonicated for 1h via an ultrasonic homogenizer by blending an organic solvent. Samples were subjected to SEM, TEM, FTIR, and UV-Vis/NIR spectroscopy investigations. After the investigations, it was shown that nano-size graphene sheets were obtained.

Multi-walled carbon nanotubes (MWCNTs) are a highly effective adsorbent of methylene blue (MB), and they can be used to remove MB from aqueous solutions. In this study, we used MWCNTs that were synthesized by chemical vapor deposition method. The physicochemical properties of MWCNTs were characterized by Brunauer-Emmett-Teller (BET) surface area, surface functional group analysis by fourier transform infrared(FTIR) analysis, zero point charge (pH(zpc)), X-ray diffraction (XRD), and transmission electron microscopy (TEM). The factors that affected the adsorption properties of MB onto MWCNTs were investigated, including initial pH, contact time, dosage, initial concentration, and temperature. The equilibrium adsorption data were analyzed using two common adsorption models, i.e. the Langmuir and Freundlich models. The results indicated that the Langmuir isotherm fits the experimental results well. The maximum adsorption capacity obtained from the equation of the Langmuir isotherm at 323K was 95.30mg/g, indicating that the MWCNTs adsorbed MB effectively. The kinetic study illustrated that the adsorption of MB onto MWCNTs fits the pseudo-second-order kinetic model. The thermodynamic parameters indicated that the adsorption of MB onto MWCNTs was a spontaneous, endothermic process.

In this study, ZnO–Fe2O3 nanocomposites were synthesized by powder metallurgy route and characterized through X-ray diffraction, UV–vis diffuse reflectance spectroscopy, scanning electron microscopy, electrical conductivity measurement device. The amount of Fe2O3 in the ZnO and milling time were varied in order to investigate their influence on the electrical and optical properties of the samples. Powder mixture containing milled and unmilled Fe2O3 at the rates of the 1, 3 and 5wt% was sintered in vacuum environment. Results show that the conductivities of ZnO–Fe2O3 nanocomposites slightly increased by increasing the Fe2O3 content and these composites have potential materials for photocatalysis. Besides, electrical and optical properties of ZnO–Fe2O3 nanocomposites varied according to status of unmilled Fe2O3 and milled Fe2O3.

Mechano-thermal method was used for synthesizing the carbon nanotubes (CNTs) in this study. In this method, graphite powders in the elemental form were firstly exposed to milling process in high-energy ball milling and then the milled powders were annealed at high temperatures. As a result of milling of the graphite, ultra-active disordered carbon structures were obtained. This structure serves as a carbon source for the formation of nanotubes during the annealing process. This study investigated the effect of the milling process. For this purpose, graphite powders were milled at different periods such as 5 and 150 h and then annealed at 1600 °C. The transmission electron microscopy and scanning electron microscopy examinations demonstrated that CNTs formed in samples milled both for 5 and 150 h. However, the difference in the milling time influenced the amount of CNTs, their size and the formation of other structures except from nanotubes.

This study reports on the thermo-mechanical synthesis of carbon nano onions from elemental graphite powders. Initially, amorphous carbon was obtained by high energy ball milling technique from graphite powders. X-ray spectra taken from ball milled samples indicated that the hexagonal graphite, composed of layers, was transformed into the amorphous carbon for a shorter milling time of 5 h by high energy input about 78 times of gravity. Subsequent isothermal annealing of milled graphite powders was conducted at 1400 degrees C for 4 h in Ar gas. It was revealed via investigation of transmission electron microscopy that carbon nano onions were formed after annealing.

In this study, graphite powder was exposed to two different stress types by using the same type of mill in order to understand the formation of different carbon nanostructures. Two types of milling modes were selected as shock-type and shear-type stresses during the milling processes. Both shock-type and shear-type stresses were applied to the graphite powder. Then, milled powders were annealed at high temperatures for different times. The structural changes in the obtained samples were determined by XRD diffraction, SEM, FE-SEM and HR-TEM examinations. New carbon nanostructures were synthesised.

In this study, carbon nanotubes were synthesized by chemical vapor deposition (CVD) process. In CVD process, milled iron powders were used as catalyst. Initially, iron powders were milled by high energy ball mill for 3h. Then, iron particles were homogeny distributed onto substrate and carbon nanotubes were obtained by CVD process inside tube reactor. Carbon nanotubes were investigated by HR-TEM to determine the effect of milled iron catalyst on nanotube formation.

In this study, carbon nanotubes were synthesized by mechano-thermal process from elemental graphite powders. Initially, high ultra-active amorphous carbon was obtained by short time milling process from graphite under inert atmosphere. Then, isothermal annealing of milled graphite powders was conducted at 1600 degrees C for 6 h in Ar gas. From the investigations of Transmission electron microscopy and Scanning electron microscopy, it was revealed that bamboo and cylindrical nanotubes were formed after isothermal annealing. In this study, nanotubes which have the diameters between 50 and 200 nm were produced at a short time ball milling process and a lower annealing temperature of 1600 degrees C although bamboo and cylindrical nanotubes are reported to be produced after ball milling of graphite for 150 h and then annealing amorphous graphite at least 1800 degrees C.