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A Ti3SnC2–Al2O3 composite was produced by mechanical alloying and subsequent differential thermal analysis (DTA) of 3TiO2/4Al/1Sn/2C powder mixture. The starting powder was milled up to 40 h. To determine the formation mechanism, a 40 h milled powder was evaluated by DTA. X-ray diffraction was used to evaluate powder samples. Later, morphological and microstructural characteristics of the samples were obtained by high-resolution scanning electron microscopy. Followed by milling, the patterns of X-ray diffraction showed a homogeneous distribution of fine reactant powders without new phases that after 40 h of milling. According to the DTA, several thermal events occurred during the 40 h of milling and Ti3SnC2/Al2O3 was formed, consequently. The formation mechanism of Ti3SnC2/Al2O3 composite consisted of Sn melting, Al melting, TiO2 reduction, Ti5Sn3 and TiC formation, and reaction among Ti, C, Ti5Sn3 and TiC, as well as Ti3SnC2 formation.

NiAl intermetallic matrix nanocomposite with TiC and Al2O3 was directly fabricated by mechanical alloying of NiO, Al, graphite, and Ti as the starting powder mixture. The phase and morphological evaluations during mechanical alloying were characterized by X-ray diffraction and scanning electron microscopy equipped by energy-dispersive X-ray spectroscopy, respectively. The thermal behavior of the 40 h milled powder was obtained via differential thermal analysis. Followed by 10 h milling, no new phases were formed; but after 20 h milling, Al reduced a fraction of NiO, NiAl and Al2O3 were formed, and the released energy promoted TiC formation. When milling time reached 40 h, the remained raw materials were completely consumed and NiAl/TiC–Al2O3 nanocomposite was formed. Therefore, the main stage to synthesize NiAl/TiC–Al2O3 nanocomposite was the reduction of NiO by Al. The microstructural evaluation revealed formation of a homogeneously distributed composite and thermal analysis showed that the synthesized product was stable.

The development of new joint configurations suitable for dissimilar materials enables a wider range of applications and allows for an accelerated replacement of traditional structural construction materials by lightweight materials. The T-configuration is a joint configuration that has not been sufficiently studied for use with dissimilar materials, especially when created using the friction stir welding (FSW) process. In this study, a combined lap/butt design was introduced and implemented, seeking to create a T-joint between aluminum and steel. Characterization of the joints showed that FSW could be successfully used to join aluminum and steel in a T-configuration. The formation of intermetallic bonds and kissing bonds was carefully analyzed, and their contribution to the fracture behavior during loading in the skin and stringer directions was studied. Finite element simulation was used to determine the stress state at the interface during loading. The characterization results showed that the intermetallic, as an indicator of metallurgical bonding, is formed when special features are observed in the pattern of material flow. The fractography images showed that the stress state has a major impact on the fracture. The results of the present study can be effectively used to design and fabricate dissimilar joints, taking into account the loading condition.

Recent advancements in synthesizing materials potential for hydrogen storage have greatly forced the hydrogen storage technology ahead in recent years. Hollow spheres, with unparalleled characteristics like low density and high specific surface area, have emerged as one of the most promising alternatives for hydrogen storage applications. In the present review, the main synthesis approaches of hollow spheres including spray drying, Kirkendall, template-free and, template-assisted methods are surveyed and concisely described. In addition, different types of hollow spheres such as hollow carbons, hollow glasses and other less-common types like Boron nitrides and metal hollow spheres have been tackled with special focus on adsorption/desorption capacities as well as the kinetic of hydrogen storage/release. In addition to the recent progresses, some perspective and outlook on the advancement of hollow spheres and challenges in terms of synthesis methods and hydrogen storage performance were presented.

In this work, NiAl-WC composite was synthesized by a mechanical activated thermal explosion process from the powder mixture of nickel, tungsten, aluminum, and graphite. The phase, morphology, and microstructure development during milling and after the thermal explosion process were evaluated by XRD, FE-SEM, and TEM-EDS analysis techniques, respectively. The results indicated that after the thermal explosion of an as-mixed powder mixture, unreacted starting powder remained, and some new phases like Al0.42Ni0.52 and W2C formed, which confirmed that the synthesis reactions were not completed. But, the final product of 5 h milled powder after the thermal explosion consisted of desired phases, NiAl and WC. XRD results of 5 h milled powder showed that the mechanical activation had two effects on NiAl-WC composite synthesis, reduction of crystallite and particle size, and better mixing of reactant powders and formation of W2C phase as an intermediate phase. These effects increased kinetics of reactions, and finally, NiAl-WC composite formed.

Friction stir welding (FSW) is a process by which a joint can be made in a solid state. The complexity of the process due to metallurgical phenomena necessitates the use of models with the ability to accurately correlate the process parameters with the joint properties. In the present study, a multilayer perceptron (MLP) artificial neural network (ANN) was used to model and predict the ultimate tensile strength (UTS) of the joint between the AA2024 and AA7075 aluminum alloys. Three pin geometries, pyramidal, conical, and cylindrical, were used for welding. The rotation speed varied between 800 and 1200 rpm and the welding speed varied between 10 and 50 mm/min. The obtained ANN model was used in a simulated annealing algorithm (SA algorithm) to optimize the process to attain the maximum UTS. The SA algorithm yielded the cylindrical pin and rotational speed of 1110 rpm to achieve the maximum UTS (395 MPa), which agreed well with the experiment. Tensile testing and scanning electron microscopy (SEM) were used to assess the joint strength and the microstructure of the joints, respectively. Various defects were detected in the joints, such as a root kissing bond and unconsolidated banding structures, whose formations were dependent on the tool geometry and the rotation speed.

The aim of the present study was to investigate the phases formed during ball milling of Al-TiO2-NiO. For this purpose, a mixture of Al-TiO2-NiO with a molar ratio of 6:1:1 was used. Characterization of the milled powders by X-ray diffraction, differential thermal analysis, field-emission scanning electron microscopy, and transmission electron microscopy showed the formation of nanocrystalline NiTi2 along with AlNi. A thermodynamical investigation confirmed that NiO was reduced by Al during ball milling, which consequently promoted TiO2 reduction and the formation of NiTi2. Al is capable of reducing NiO either during ball milling or at temperatures above the melting point of Al; by contrast, TiO2 can be reduced by Al only by milling.

The aim of this study was the synthesis of a homogenous distributed NiAl/TiC composite by combustion synthesis of elemental powders. The effect of the mechanical activation process was evaluated. The phase characterization and evaluation of the microstructure during milling and combustion synthesis were carried on by XRD and SEM-EDS and TEM-EDS, respectively. The XRD result of as-mixed powder compact after combustion synthesis showed that in addition to TiC0.75 and NiAl, some undesired phases like Ni3Al and Ni2Al­3 formed. While after combustion synthesis of 3h mechanically activated powder compact, only AlNi and TiC formed. The microstructural evaluations by SEM-EDS and TEM-EDS analysis confirmed the synthesis of truly homogenized NiAl/TiC composite. The mechanism of NiAl/TiC formation consists of dissolution of nickel, titanium, and graphite in molten aluminum and precipitation of TiC primarily and then the formation of NiAl. The value of microhardness of synthesized NiAl/TiC was 1070±12 HV. The main reason for this result is a uniform distribution of spherical TiC reinforcement in the NiAl matrix. Therefore, the mechanical activation process facilitated the reactions and improved the mechanical properties of the final composite.

The purpose of this study was to produce Fe3Al/TiC-SiC nanocomposite by mechanical alloying of the FeSiTiO3, Al and C powder mixture. The phases made of the samples were characterized by XRD. The morphological evolution was analyzed during mechanical alloying by FESEM. The particle size of the 30 h milled powder was determined by TEM. The results showed that ball milling led to the formation of SiC after 10 h. Increasing of milling time to 20 h caused TiCx and Fe3Al were formed with remained TiO2 phase. After 30 h milling, all peaks of TiO2 phase eliminated and Fe3Al/TiC-SiC nanocomposite was formed. The XRD investigation of the powders after annealing showed that no new phases were formed. TEM image confirmed that average particle size of syntehsized powder after 30 h milling was 60 nm.

A383 aluminum alloy high pressure die castings were solution treated at 490 °C for six durations ranging between 15 and 180 min, subsequently quenched in water and naturally aged for 4 days. The effect of solution treatment time on the evolution of microstructure and tensile properties were determined previously (G. Eisaabadi et al. Mater. Sci. Eng. A, 722, pp. 1–7, 2018.) In the current study, the tensile deformation characteristics of A383 alloy castings were determined by analyzing work hardening rate versus true stress in Kocks-Mecking plots. Results showed that (i) there was a sudden drop in work hardening rate immediately prior to fracture in all specimens, (ii) some specimens exhibited Portevin-Le Chatelier (PLC) effect, (iii) the stress where the PLC effect started increased with yield strength, (iv) the unitless Kocks-Mecking parameter, K. decreased with increasing solution treatment time, and there was a strong relationship between K and elongation (v) the main benefit of prolonged solution treatment of cast aluminum alloys is healing of structural defects, namely oxide bifilms. These results are discussed in detail in the paper.

This paper introduces a new model for prediction of tensile properties of Al A357 castings in the form of UTS (MPa) = a + b ln (G/√Ṫ) and El (%) = c + d ln (G/√Ṫ). While previous models use only SD...

In-vitro batch adsorption of cholesterol from human blood serum was investigated using Thymus vulgaris L. (Thyme) as a biocompatible adsorbent. X-Ray Diffraction technique (XRD), Scanning Electron Microscopy (SEM), and Fourier Transform Infrared spectroscopy (FTIR) were selected to characterize the biosorbent. The pseudo-first-order, pseudo-second-order, Elovich and intraparticle diffusion models were employed to study the adsorption kinetic with the intraparticle diffusion and pseudo-second order models providing superior fits. Kinetic results also showed that the time required for the equilibrium was around 2 h. The Langmuir, Freundlich, Temkin and Dubinin–Radushkevich isotherms were also applied to investigate the adsorption equilibria at ambient temperature. The Langmuir model provided superior agreement with the equilibrium data and the adsorption capacity was around 84.74 mg/g. The results showed that the cholesterol removal increased from 30% to 50% with increased adsorbent mass from 0.01 to 0.1 g; meanwhile, removal did not noticeably vary (∼7%) with further adsorbent dose increase from 0.1 to 0.2 g. The coarse Thyme powder indicated higher cholesterol removal (46%) compared to the milled (38%), due to aggregation of the latter in the serum environment. Based on the results, Thymus is an effective biosorbent for application in extracorporeal serum perfusion.

A383 aluminum alloy high pressure die castings were solution treated at 490 °C for six duration ranging between 15 and 180 min, subsequently quenched in water and naturally aged for 4 days. The effects of solution treatment time on the evolution of microstructure and tensile properties were determined. As expected, Si particles became larger and rounder with increasing solution treatment time. In all cases, the size and aspect ratio of the Si particles followed the lognormal distribution. Moreover, the coarsening of Si particles during solution treatment was found to follow the Lifshitz –Slyozov-Wagner model. A new equation was developed for the evolution of the aspect ratio during solution treatment of Al-Si-Mg alloys. Analysis of tensile properties showed that elongation and quality index increased steadily with increasing Si particle size, a result that is in contrast with the widely accepted notion that large Si particles impairs the ductility of cast Al-Si-Mg alloys. The positive correlation between Si particle size and quality index was interpreted to be due to partial healing of oxide bifilms entrained in the castings.

In-situ Al matrix composite was synthesized from Al–TiO2–C powder mixtures using mechanical alloying and heat treatment, subsequently. The effect of ball milling on reaction processes of the resulting nanocomposite was investigated. The evaluation of powder mixture without mechanical activation showed that at 900°C aluminum reduced TiO2, forming Al3Ti and Al2O3. After 20 h mechanical activation of powder mixture, Al3Ti and Al2O3 were fabricated. After that, by increasing milling time up to 30 h, no new phases formed. The DTA analysis of 30 h milled powder indicated two peaks after aluminum melting at 730 and 900°C. The XRD results confirmed that at 730°C, molten Al reacted with TiO2 and C, forming Al3Ti, Al2O3 and Al4C3. After that, at 900°C, Al3Ti reacted with Al4C3, causing TiC formation. This results proposed that the TiC formation is associated by a series of reactions between intermediate products, Al3Ti and Al4C3 and the resultant nanocomposite was successfully synthesized after 30 h milling and heated by DTA analysis up to 1200°C.

Commercial pure aluminum was friction stir processed with Al-TiO2-graphite mixture pre-placed into a groove in Al. Two kinds of powders were used as starting particles for friction stir processing; as-mixed powder and 60-h ball-milled powder. Characterization by XRD, SEM and EDS analysis showed that with as-mixed powder an Al composite reinforced with Al3Ti and Al2O3 was produced. Graphite particles were remained in the matrix unchanged. Using 60-h ball-milled powder as starting particle in friction stir processing, resulted in an Al composite reinforced with TiC-Al2O3 nanoparticles dispersed uniformly into the matrix having the size of 100 nm on average. In this state, the microhardness values obtained in the stir zone were higher than those ones obtained using as-mixed powders. The mechanism of phases formation during friction stir processing with two different kinds of powders are elaborated and discussed in this study. Also the mechanical properties of samples were investigated.

A feasible approach to fabricate an Al(Cu)-based hybrid nanocomposite reinforced with TiC and Al 2 O 3 based on mechanical activation and post heat treatment was proposed. Structural and phase evolution during mechanical alloying were studied by employing X-ray diffraction (XRD), transmission electron microscopy (TEM), filed emission scanning electron microscopy (FESEM) and differential thermal analysis (DTA) techniques. Mechanical alloying method was used in order to formation of Al(Cu), TiO 2 /Al 3 Ti, Al 4 C 3 powder. It was found that a powder mixture of Al(Cu), TiO 2 /Al 3 Ti, Al 4 C 3 is formed after 30 h of milling. The XRD analysis showed that Al(Cu)/TiC-Al 2 O 3 is synthesized after heat treating of powder mixture at 1000 °C for 1 h via reaction between Al 3 Ti, Al 4 C 3 and TiO 2 . DTA analysis showed that Al(Cu)/TiC-Al 2 O 3 cannot be synthesized without mechanical activation and only based on heat treating. It was shown that heat treating of the as-milled powder mixture for 50 h at 500 °C doesn’t lead to formation of Al(Cu)/ TiC-Al 2 O 3 composite and a minimum temperature of about 1000 °C is needed for synthesis of Al(Cu)/ TiC-Al 2 O 3 hybrid composite.

Introduction: Hymenolepis nana is a zoonotic tapeworm with widespread distribution. The goal of the present study was to identify the parasite in the specimens collected from NorthWestern regions of Iran using PCR-sequencing method. Methods: A total of 1521 stool samples were collected from the study individuals. Initially, the identification of hymenolepis nana was confirmed by parasitological method including direct wet-mount and formalin-ethyl acetate concentration methods. Afterward, PCR-sequencing analysis of ribosomal ITS2 fragment was targeted to investigate the molecular identification of the parasite. Results: Overall, 0.65% (10/1521) of the isolates were contaminated with H. nana in formalin-ethyl acetate concentration. All ten isolates were succefully amplified by PCR and further sequenced. The determined sequences were deposited in GenBank under the accession numbers MH337810 -MH337819. Conclusion: Our results clarified the presence of H. nana among the patients in the study areas. In addition, the molecular tech- nique could be accessible when the human eggs are the only sources available to identify and diagnose the parasite. Keywords: Hymenolepis nana, rDNAITS2, PCR, Iran.

A novel approach has been developed to fabricate a thin layer of titanium oxide (TiO2) on the surface of 316L stainless steel by a combination of Sol-Gel method and subsequent active screen plasma annealing (ASPA) method. Dip coated layers were plasma annealed in a titanium cylindrical mesh from 300 to 500 ℃. The effect of ASPA temperature on the particles size, morphology, and crystallinity of the coating layers was studied in comparison with conventional annealing. Also, electrochemical impedance spectroscopy and potentiodynamic polarization were employed to study the corrosion behavior of both types of coatings. The results showed that, a crack-free TiO2 coating with a thickness of about 1–5 μm can be obtained using the ASPA method at different calcination temperatures. Plasma annealing led to the decline of calcination temperature and formation of nanostructured anatase phase with higher crystallinity and structural uniformity in comparison to conventional annealing method. Moreover, the corrosion resistance of the coating was significantly increased compared to conventional annealing method. It was found that, the coating of titanium oxide can reduce by eight-fold the corrosion rate of 316L stainless steel.

The formation mechanism of Ti3SnC2 was evaluated in the present work. A stoichiometric ratio of a Ti-Sn-C powder mixture was prepared and milled for 50 h. To synthesize and detect intermediate reactions, a 50 h milled sample was thermally analyzed by STA. XRD instrument was utilized to detect phases of powder samples and the microstructure of the final product was obtained by SEM. The results showed that only Ti6Sn5 and Ti5Sn3 with Fe3Sn2 formed after 50 h milling, and no peaks related to MAX phases were found. To detect the reaction mechanism, the 50 h milled powder after STA analysis was characterized by XRD. Many intermediate reactions such as TixSny, TiC, and Ti2SnC formations took place. The melting of FexSny during STA analysis promoted the Ti3SnC2 formation. These results confirmed that Ti3SnC2 formation is not happened by a single reaction and many intermediate phases must be formed and Ti3SnC2 was synthesized after 50 h ball milling and thermally treated by STA analysis to 1400 °C.