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High entropy alloy (HEA) with shape memory effect (SME) has been the subject of great interest for the past few decades. However, with the increased demands for new materials for high thermal applications, the research activities on the multi elemental high entropy shape memory alloys (HESMA) have been increased by many folds recently. The nano crystalline HEA powder with shape memory effect developed in this study, HfZrTiFeMnSi, was produced by mechanical alloying (MA) for the first time. In this method equiatomic ratio of Hf, Zr, Ti, Fe, Mn, and Si were mixed together and milled by MA process for 100 h. The powder formed was of amorphous in nature. Elemental mapping of the powder from SEM-EDS revealed homogeneity of the alloying elements confirming successful fabrication of HfZrTiFeMnSi HEA powder. The DSC studies from ambient to 500 °C of the annealed alloy powders showed reversible austenitic to martensitic (A↔M) transformations. The A↔M transformation hysteresis seemed to vary with the milling time and annealing temperature. The enthalpy values, ΔH, for the transformation were calculated from the DSC plots using tangent method for peak area calculation. Regardless of the annealing temperature, the thermal analysis revealed that the ΔH, equilibrium temperature (T0), and crystallization temperature values decreased with the increasing milling time.

Aluminum-Boron Carbide (Al-B4C) metal matrix composites (MMCs) are frequently studied because of their high thermal conductivity and ability to absorb neutrons, as an alternative material for the manufacture of baskets in spent fuel casks in the nuclear industry. Keeping in mind, this study aimed to produce Al-B4C MMCs and examine their properties to shield against neutron radiation. The Al-xB4C (x = 5, 10, 15, 20, 25, 30, 40, 45, and 50 wt%) composite powders were prepared by a high-energy planetary ball milling. The prepared powders were com-pacted with uniaxial cold compaction at 500 MPa and sintered in a tube furnace at 600 degrees C for 1 h under an Argon atmosphere. The microstructure of the obtained MMCs was characterized by using X-ray diffraction (XRD) and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM/EDX). The XRD result indicates that the synthesized Al-B4C MMCs have a predominant phase of Al and B4C. The SEM images show the distri-bution of B4C reinforcement inside the Al matrix. The relative density, measured by the Archimedes principle decreased from 99.95 to 91.55% as the B4C ratio increased. The microhardness value was increased in the beginning from 44 to 75.5 HV and then decreased to 36.5 HV as the B4C ratio increased. The polarization curves show that the corrosion current density and the corrosion rate were significantly increased from 52.25 to 375.36 mu A cm-2 and 0.573-4.121 mm/year as the B4C ratio increased. The simulation results, computed by the MCNP6.2 program show that the thermal neutron cross-section and the fast neutron cross-section was increased from 4.5 to 40.1 cm-1 and 0.13 to 0.15 cm-1 as the B4C ratio increased. Further, the neutron equivalent dose rate was calculated experimentally with the 241Am-Be neutron source and the data was completely agreed with the computational results., Scientific Research Projects Coor-dination Unit of Zonguldak B?lent Ecevit University; [2020-73338635-01], This work was supported by the Scientific Research Projects Coor-dination Unit of Zonguldak B?lent Ecevit University with project no. 2020-73338635-01.

This paper delineates a single-step production method of nanostructured diiron boride (Fe2B) and its structural, magnetic and magnetothermal properties. Structurally Fe2B resembles the tetragonal copper aluminide, CuAl2. The samples of nanostructured Fe2B were synthesized by milling Fe and B powders without any pre-treatment. Single phase Fe2B nanoparticles were successfully produced with the crystallite sizes of 68 and 46 nm after milling the powders for 10 h and 20 h, respectively. The saturation magnetization of the samples was found to decrease with increased milling time indicating that the surface spin disorder plays a crucial role in the magnetic properties. The highest saturation magnetization (Ms) of 141 emu/g with low coercivity (Hc) of 48 Oe was obtained for the 10 h milled sample of Fe2B, whereas the 20 h milled sample exhibited Ms and Hc as 129 emu/g and 149 Oe. This paper also presents a detailed information on the total and atom projected densities of state functions as well as the magnetic moment contribution of the individual atoms of Fe and B in Fe2B explaining the strong room temperature ferromagnetic properties contributed by the large number of unpaired 3 d electrons in Fe. The magnetothermal properties of the as-made Fe2B nanocrystals of high magnetic moment were investigated by measuring the rise in temperature as a function of time in the presence of AC magnetic fields. The magnetic Fe2B nanocrystals show significant thermal response with the high specific absorption rate of 172 W/g, demonstrating the advantages of using Fe2B nanocrystals for the application in magnetic fluid therapy for hyperthermia.

It is very much essential to produce high-purity metals and alloys using efficient technology for industrial applications. Keeping the above in mind, cobalt monosilicide (CoSi) intermetallic alloy powder preparation using mechanical alloying approach with its microstructural and magnetic properties was studied in detail. Therefore, CoSi intermetallic alloys, thermoelectric, and soft magnetic material powders were prepared using the above approach. The mechanical alloying approaches were accomplished at a speed of 400 rpm under inert atmosphere to prevent oxidation. The structural and morphological properties were analyzed using X-ray diffraction (XRD) and scanning electron microscopy and energy-dispersive X-ray spectroscopy (SEM/EDX) instruments. The results revealed that the starting elemental ingredients powder mixtures were fully transformed into CoSi intermetallic alloy after 96-h of milling duration. The magnetic properties, like the saturation magnetization (Ms) and coercivity (Hc) of the various mixed powdered samples during the milling duration were calculated from the hysteresis loops, which were determined using the vibrating sample magnetometer (VSM) instrument. The Ms and the Hc values were 7.18 emu/g and 36.25 Oe, respectively while milling the powder mixtures for 96 h, which indicates the CoSi intermetallic alloy.

Bu çalışmada, nanoyapılı Fe (Al,Cu) katı çözeltisi, elementel tozların mekanik alaşımlama (MA) işlemi ile sentezlenmiştir. Toz karışımlar, 50 saatlik öğütme süresince çeşitli zaman aralıklarında gezegensel bilyeli değirmende öğütülmüştür. Numunelerin yapısal ve mekanik özellikleri X-ışını difraksiyonu (XRD), taramalı elektron mikroskobu/ enerji dağılımlı X-ışını spektroskopisi (SEM/ EDX) ve Vickers mikrosertlik (HV) testi ile incelenmiştir. 10 saatlik öğütme işleminden sonra bütün Al ve Cu atomları ymk-Fe (Al,Cu) katı çözeltisini oluşturmak üzere Fe kafesi içerinde çözünmüştür. Toz alaşımların parçacık morfolojisi öğütme süreleri boyunca soğuk kaynaklanma, kırılma ve kararlı durum aşamalarını göstermiştir. 50 saatlik öğütme işleminden sonra parçacık boyutu ve kristalit boyutu, sırasıyla ~ 500 nm ve ~ 6 nm’ ye düşmüştür. Bununla birlikte, mikrosertlik değerleri artan öğütme süresiyle birlikte artmıştır.

The soft ferromagnetic materials are of great industrial importance for their applications in magnetic cores for transformers, electric motors, inductors, and generators. In recent years, the trend has been to use magnetic high entropy alloys (HEAs) owing to their superior magnetic properties compared to the conventional magnetic materials. In this study, the traditional magnetic materials, (NiFeCo)95Mo5 and (NiFeCo)90Mo10 produced by conventional mechanical alloying method, were compared with the NiFeCoMo high entropy alloy produced by the sequential mechanical alloying method. Unlike conventional mechanical alloying, NiFeCoMo HEA was produced by mechanical alloying using sequential additions of Co and Mo to the preformed Fe-Ni alloy. Besides its magnetic properties, the effect of Co and Mo on the overall characteristics of the alloy was also investigated. In 60 h milled samples of the (NiFeCo)95Mo5 and (NiFeCo)90Mo10 alloys, the crystallite sizes were estimated as 10.5 and 10.8 nm respectively, whereas the crystallite size for the NiFeCoMo HEA was 15 nm. The presence of Mo in the alloy induced the formation of lamellar or layered structures of the particles. During the sequential milling to form NiFeCoMo HEA, it was noticed that the addition of Co into the preformed Fe-Ni alloy increased the magnetic saturation value due to the formation of FeCoNi alloy phase. However, further addition of Mo into the FeCoNi alloy phase reduced the magnetic saturation value of NiFeCoMo alloy significantly. After 60 h of milling the magnetic saturation value was dropped from 102.48 emu/g for the NiFeCo alloy to 60.52 emu/g for the NiFeCoMo alloy.

A rapid and easy synthesis of pure neodymium hexaboride, NdB6 nanocrystals was developed, without applying heat treatments at high temperatures. The mechanochemical synthesis of NdB6 powders was performed at room temperature inside a planetary ball mill. The Nd, B2O3 and Mg starting blends were mixed, and subsequently mechanically alloyed to constitute NdB6-MgO as final products. The effect of milling duration on the NdB6 formation mechanism and metallothermic reduction was investigated. Following mechanochemical synthesis, MgO was removed from the system by leaching the powders with CH3COOH solution. The formation of NdB6 phase was monitored by the X-ray diffraction (XRD) analysis. Microstructure and morphology of the synthesized nanocrystals were characterised by using scanning electron microscopy/energy dispersive x-ray spectroscopy (SEM/EDS), and high resolution transmission electron microscopy (HRTEM) techniques. Pure NdB6 nanocrystals with a crystallite size of 18.2 ± 2.0 nm were obtained after 15 h of milling. Microscopic investigations revealed the irregular shape and morphology of NdB6 nanocrystal structures. Rietveld refinements confirm the cubic structure (space group Pm-3m) with a lattice constant of 4.1254 (2) Å and 92 ± 8 nm particle size of NdB6 phase. The Raman active phonons of Pm-3m symmetry were characterised by Raman spectroscopy. © 2019 Elsevier B.V.

Nanostructured (FeCoNi)70Ti10B20 (at%) alloy was synthesized by mechanical alloying from elemental powder mixture of Fe, Co, Ni, Ti and B using ball milling. The effect of ball milling time on the evolution of structure and morphology was investigated by X-ray diffraction, scanning and transmission electron microscopy and differential thermal analysis. It was observed that the formation of solid solution of (FeCoNi)70Ti10B20 started from the very onset of the milling process. Crystallite size and lattice strains seemed to be leveled off after 20 h of milling with no further major changes. The milling process for longer periods introduced severe plastic deformations causing formation of amorphous phase of (FeCoNi)70Ti10B20. The amorphous alloy composition was confirmed by energy dispersive X-ray spectroscopy analysis that showed an excellent homogeneity of the alloying elements. The phase stability of the mechanically alloyed amorphous sample was further verified by employing high-temperature and high-pressure studies. The alloy samples heat-treated at 700 °C revealed crystallization of the amorphous phase. However, synchrotron-based high-pressure ambient temperature X-ray diffraction studies confirmed that the amorphous phase of the alloy remained stable up to the pressure of 30 GPa. The 50 h milled sample after being annealed at 350 °C showed improvement in the soft magnetic properties of the alloy, which was due to the probable elimination of the residual stress in the amorphous phase of the alloy powders.

In this work, nanocrystalline Co65Ti25W5B5 (at.%) powders were prepared by mechanical alloying (MA) of the elemental powder mixture under argon gas atmosphere. The powders were milled during different periods (2.5, 5, 10, 20 and 30 h) using a planetary ball-mill (Retsch PM100 CM) at 400 rpm. The structural, morphological, thermal and magnetic properties of the nanocrystalline Co65Ti25W5B5 powders were studied by means of X-ray diffraction (XRD), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM/EDX), differential thermal analysis (DTA) and vibrating sample magnetometer (VSM) techniques. Because of its high melting point, hardness and low solubility in the alloy components, a small amount of tungsten remained in the amorphous matrix during MA. By using the Williamson-Hall method, the crystallite size and lattice strain of the tungsten phase were calculated as about 25 nm and 0.48% respectively, for 30 h of milling. The DTA curves of the milled powders demonstrated an exothermic peak at about 600 °C, indicating the crystallization of the amorphous phase. The apparent mean activation energy, 303.5 ± 7 kJ/mol for 20 h milled powders was determined by Kissenger and Ozawa methods. The saturation magnetization (Ms), the coercivity (Hc) and the remanence-to-saturation ratio (Mr/Ms), values were of about 66 emu/g, 11 Oe and 0.012 respectively, after 30 h of milling. © 2015 Elsevier B.V.

Buçalışmada nanokristal Co70Si15B15 (at.%) tozalaşımları, mekanik alaşımlama (MA) tekniği ile farklı öğütme sürelerindeüretilmiştir. Öğütme süresince alaşımların yapısal değişimleri, parçacıkmorfolojisi, termal kararlılıkları ve manyetik özellikleri incelenmiştir. X-ışınıdifraksiyonu (XRD) sonuçları, elementel tozların birbirleri ile olan reaksiyonusonucu nanokristal Co(Si,B) katı çözelti fazını oluşturduğunu göstermiştir.Taramalı elektron mikroskobu (SEM) analizlerinden morfolojinin alaşımlamaboyunca değiştiği ve parçacık boyutunun öğütmenin ilk safhalarında arttığı,daha sonra küçüldüğü anlaşılmıştır. Alaşımların yapısal durumuna bağlı olarakgörülen ekzotermik reaksiyonun aktivasyon enerjisi 128 ± 3 kJ/mol olarakhesaplanmıştır. Manyetik sonuçlar, artan öğütme süresiyle hem doyummanyetizasyonunun (Ms) hem de koersivitenin (Hc)azaldığını göstermiştir., Inthis research, nanocrystalline Co70Si15B15(at.%) powder alloys were prepared by mechanical alloying (MA) technique atvarious milling times. Their structural changes, particles morphology, thermalstability and magnetic properties through the milling process wereinvestigated. The X-ray diffraction (XRD) results showed that reaction of theelemental powders mixture resulted in the formation of the nanocrystallineCo(Si,B) solid solution phase. According to the scanning electron microscopy(SEM) analysis, particle morphology was changed during alloying and theparticle size increased initially, then decreased. Depending on the structuralstate of the alloys, the apparent activation energy of the exothermic reactionwas calculated as 128 ± 3 kJ/mol. Magnetic results indicated that bothsaturation magnetization (Ms) and coercivity (Hc) weredecreased with increasing milling time.

In this work, ZnO and boron doped ZnO (ZnO:B) thin films were produced by chemical spray pyrolysis method. ZnO and ZnO:B films were obtained onto glass substrates at 450°C by spray pyrolysis method and the physical properties of those films were examined by X-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet-visible spectrometer (UV) and four probe technique. XRD measurements show that all films have hexagonal wurtzite structure and all films grow preferentially along (002) direction. Morphologies of the films were examined by using a scanning electron microscopy and it was observed that almost all films were quite intense with a regular structure. Optical measurements showed that the band gap energies of the films increased with boron concentrations. The resistances of the B-doped ZnO films were measured by four probe method and resistances of films initially decreased to its minimum 1 at% boron doping and then it increased again with increasing B concentration. It was also observed that that boron doping increased the activation energies of the films. © 2015, Pleiades Publishing, Inc.

Bu çalışmadananoyapılı Al85Co7Y8 (at.%) alaşımı, mekanikalaşımlama (MA) tekniği kullanılarak elemental tozların katı hal reaksiyonuylasentezlenmiştir. Toz alaşımlar, argon gazı altında sertleştirilmiş paslanmazçelik hazne ve bilyeler kullanılarak yüksek-enerjili bilyeli değirmeniçerisinde 300 saatlik öğütme işlemine tabi tutulmuştur. Öğütme işlemi süresincenumunelerdeki yapısal ve morfolojik değişimler X-ışını difraksiyonu (XRD) vetaramalı elektron mikroskobu (SEM) ile termal kararlılıkları ise diferansiyeltermal analiz (DTA) ile incelenmiştir. MA işlemi sonucunda aşırı doymuş fcc-Alkatı çözelti fazı içeren alaşımlar üretilmiştir. Al85Co7Y8alaşımının 300 saatlik öğütme işlemi sonrasındaki kristalit boyutu yaklaşık 16nm olarak bulunmuştur., Inthis study, the nanostructured Al85Co7Y8(at.%) alloy was synthesized by a solid state reaction from the constituentelemental powder mixture via mechanical alloying (MA). The powder mixture wasball milled for times up to 300 h in a planetary high energy mill usinghardened steel media under argon atmosphere. Structural and morphologicalchanges during the milling process were characterized by a combination of X-raydiffraction (XRD) and scanning electron microscopy (SEM) techniques. Thermalstability of the milled powders was investigated using differential thermalanalysis (DTA). The results showed that supersaturated α-Al solid solution wasformed in the whole content of the milled material. The mechanically alloyed Al85Co7Y8powder for 300 h of milling indicated the formation of fine nanoparticles witha size of about 16 nm.

Both boron (1, 2 and 3 at %) and fluorine (1, 3, 5 and 7 at %) doped zinc oxide thin films (ZnO:B:F) were fabricated using zinc chloride precursor by airbrush spray pyrolysis technique on glass substrates. X-ray diffraction (XRD) measurements show that all ZnO:B:F films have hexagonal wurtzite structure with a preferential growth along the [0 0 2] direction on glass substrates. Scanning electron microscope (SEM) results show that the morphologies of all doped films have a regular hexagonal shape. The optical measurements reveal that ZnO:B:F films have a direct band gap and optical energy gaps are increasing with boron and fluorine concentration. The optical transmittance of B and F doped ZnO films is measured very low due to columnar structure of prepared films. Moreover, it has been observed that the doping of ZnO films with boron and fluorine decreases the electrical resistance, and the lowest resistances of films were observed at 1%B–3%F and 2%B–3%F concentrations. © 2014, Pleiades Publishing, Ltd.

In this study, nanocrystalline Ti and TiO2 powders were synthesized by wet milling of Ti powder within water and reactive milling of Ti powder under oxygen atmosphere, respectively. The wet milling processes were performed at 300 rpm milling speed for different milling durations (6, 12, 24, and 48 h). Subsequent heat-treatments of the as-milled powders were performed at 200-800 °C for 1 h in an air atmosphere. Structural characteristics of the as-milled and the heat-treated powders were investigated by X-ray diffraction (XRD). The crystallite size, lattice strain and lattice parameters of the powders were also calculated. It has been realized that during the wet milling process, elemental Ti powder undergoes an hcp to fcc polymorphic transformation, which is related to grain refinement and plastic strain. In addition, TiO 2 powders are produced after heat-treatments at 600 and 800 °C. Reactive milling of the elemental Ti powder in pressurized oxygen atmosphere leads to nanocrystalline TiO2 powders with an average crystallite size of about 10 nm after 48 h milling time. The subsequent heat-treatments of the as-milled TiO2 powders results in the increase of the crystallite size up to 70-150 nm. In order to understand the thermal behavior of the as-milled powders, thermal analysis (DTA) and thermogravimetric analysis (TGA) were employed. The activation energy of the nanocrystalline TiO2 powders was determined by the Kissinger method is 128±3 kJ/mol. © 2014 Elsevier Ltd and Techna Group S.r.l. All rights reserved., 0901-602006, We would like to thank Hacettepe University , Scientific Research and Development Office, through the Grant (no. 0901-602006 ) and TUBITAK-BIDEP postdoctoral research fellowship.

The alloys with different compositions in the Al-rich corner of the Al-Co-Y ternary system were prepared by conventional casting and further processed by melt-spinning technique. The microstructure and the thermal behavior of the alloys were analyzed by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and differential thermal analysis (DTA). It was found that only rapidly solidified Al85Co7Y8alloy exhibited the best glass forming ability (GFA) and a fully amorphous structure. Besides, Al85Co13Y2and Al85Co2Y13alloy ribbons were fully crystalline, whereas Al85Co10Y5and Al85Co5Y10alloy ribbons consisted of some crystalline phases within an amorphous matrix. The SEM results showed the same trend that the crystalline phase fraction decreases with the approaching into best glass former. From DSC results, only Al85Co7Y8amorphous alloy exhibited a glass transition temperature (Tg) at 569 K, and its supercooled liquid region (ΔTx=Tx−Tg) was found to be 17 K. Moreover, other calculated GFA parameters for this alloy system were also discussed.

Amorphous Mg61Cu24Y15 ribbons were manufactured by melt-spinning at wheel speeds in the range 5–20 ms−1. The crystallization behavior of amorphous ribbons was investigated by a combination of differential scanning calorimetry (DSC) and X-ray diffractometry. DSC measurements showed that the amorphous ribbons exhibit distinct glass transition temperature and wide supercooled liquid region before crystallization. During continuous heating three exothermic peaks and two endothermic peaks were observed. The characteristic thermodynamic parameters such as T g, T x , ΔT x , and T rg are around 432–439, 478–485, 46–54 K, and 0.55–0.56, respectively. Isothermal annealing DSC traces for this amorphous alloy, the first crystallization peak showed a clear incubation period and Avrami exponent was found to be 2.30–2.74, which indicate that the transformation reaction involved nucleation and three-dimensional diffusion controlled growth. Mechanical properties of the as-quenched and subsequently annealed ribbons were examined by Vickers microhardness (HV) measurements. Results showed that microhardness of the as-quenched ribbons were about 309 HV. However, the results also showed that microhardness of the rapidly solidified ribbons increases with the increasing temperature.

In this study, the microstructures and mechanical properties of conventionally solidified Al 63 Cu 25 Fe 12 alloy after different heat-treatments were investigated. The microstructures of the as-cast and subsequently heat-treated samples were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and differential thermal analysis (DTA). The XRD results showed the presence of quasicrystalline icosahedral phase (i-phase) together with crystalline phases corresponding to β-AlFe(Cu) solid solution phase (β-phase) and τ-AlCu(Fe) solid solution phase (τ-phase). The SEM investigations clearly showed the formation of i-phase with pentagonal dodecahedra structure. However, the i-phase together with β-phase was also observed in the heat-treated samples and the peak intensity of the β-phase decreased with increasing heat-treatment temperature. From the DTA curves, the melting point of i-phase was determined as 890 °C for this alloy composition. Mechanical properties of the as-cast and subsequently heat-treated samples were measured by a Vickers indenter. Results showed that the microhardness ( HV ) and the elastic modulus ( E ) of the as-cast sample were around 598 kg fmm −2 (5.86 GPa) and 104 GPa, respectively. In addition, the characteristic of material plasticity ( δ H ) value was calculated to be 0.54.

A new ONNO-type azomethine ligand, 2,2′-(ethane-1,2-diylidenedinitrilo)dibenzoic acid, (YLH2) (1) has been prepared by the condensation of 2-aminobenzoic acid and glyoxal. The coordination compounds [Ni(YL)] (2), [Co(YL)] (3), [Cu(YL)(H2O)] (4), [Zn(YL)] (5), and [Cd(YL)] (6) of the YLH2 ligand with five transition metal ions, Ni(II) Co(II), Cu(II), Zn(II), and Cd(II) have been prepared. The structures of these new azomethine compounds are proposed on the basis of the elemental analyses, proton nuclear magnetic resonance, infrared, ultraviolet–visible spectroscopy, and X-ray powder diffraction patterns. Elemental analyses indicate a ligand metal ratio of 1:1 in the coordination compounds. X-ray powder diffraction parameters for [Cu(YL)(H2O)] and [Cd(YL)] compounds correspond to orthorhombic and monoclinic structures, respectively. The ligand acts as a tetradentate ligand bending through oxygen atoms of the hydroxyl groups of benzoic acid and nitrogen atoms of the azomethine groups. In addition, the ligand and its metal complexes have been studied for their possible genotoxic potential. © 2011 Wiley Periodicals, Inc. Heteroatom Chem 22:119–130, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/hc.20665

Quasicrystalline phase formation during heat treatment in the mechanically alloyed Al65Cu20Fe15 powders was studied by X-ray diffraction (XRD) and differential scanning calorimeter (DSC). The mechanical alloying was performed at speed of 300 rev min–1 for times up to 70 h. It was found that mechanical alloying of the Al65Cu20Fe15 powders did not result in the quasicrystalline (QC) icosahedral phase (i-phase) formation. The long time milling resulted in the formation of a cubic Al (Cu,Fe) solid solution phase (β-phase). The cubic Al (Cu,Fe) solid solution identified as β-phase was observed to be present as one of the major phases in the Al65Cu20Fe15 alloy. The formation of the quasicrystalline icosahedral phase (i-phase) was only observed for short time milled powders after additional annealing at temperature above 500°C. The present investigation also showed that a tetragonal Al2Cu phase (θ-phase) forms with short time milling. The tetragonal Al7Cu2Fe1 phase (w-phase) was observed after heat treat...

The present research aimed to characterize the microstructure of icosahedral quasicrystalline phase (i-phase) in different chemical compositions of Al–Cu–Fe alloys. The ternary alloys with the nominal compositions of Al70Cu20Fe10, Al65Cu20Fe15 and Al63Cu25Fe12 (at%) were rapidly solidified by melt-spinning technique. The melt-spun ribbons were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and differential thermal analysis (DTA). According to the XRD results, diffraction patterns of Al70Cu20Fe10 alloy showed the presence of the i-phase together with tetragonal θ-Al2Cu phase. However, XRD pattern of the melt-spun Al63Cu25Fe12 alloy showed the formation of i-phase together with a small amount of β-phase. The single quasicrystalline phase was observed only in the rapidly solidified Al65Cu20Fe15 alloy. The SEM examinations showed that the melt-spun Al70Cu20Fe10 and Al63Cu25Fe12 alloys composed of i-phase with an average grain size of 1–5 μm. However, for the Al65Cu20Fe15 alloy, the quasicrystalline particles in the star-shape dendritic formations were observed. The melting point of i-phase was determined as 890 °C by DTA examinations.

In this work, the multicomponent Co60Fe5Ni5Ti25B5 (at.%) alloy powders were synthesized from commercially available pure elemental powders by using a mechanical alloying (MA) process under argon gas atmosphere. The changes in structural, morphological, thermal and magnetic properties of the processed powders during MA were examined by X-ray diffraction (XRD), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM/EDX), differential thermal analysis (DTA) and vibrating sample magnetometer (VSM). The results showed that the amorphization occurred after 3.5 h of milling, and the amorphous phase was stable up to 580 degrees C, where crystallization occurred. The SEM observations indicated that different morphologies were obtained during the MA stages. In addition, the EDX mapping confirmed the uniform distribution of elemental content. Magnetic results indicated that all the samples exhibited soft-ferromagnetic behavior. The evolution of the saturation magnetization (Ms), the coercivity (Hc) and the squareness ratio (Ms/Mr) during milling process were discussed with respect to microstructural changes. The influence of the annealing on magnetic hysteresis was also studied. The Ms, Hc and Ms/Mr values of about 53.4 emu/g, 7.6 Oe and 0.01, respectively was obtained after 7 h of milling. (C) 2015 Elsevier B.V. All rights reserved.

A new, substituted 2-[(E)-{[4-(benzyloxy)phenyl]imino} methyl]-4-[(E)-(4-nitrophenyl)diazenyl]phenol azo-azomethine ligand (mbH) was synthesized from 2-hydroxy-5-[(4-nitrophenyl)diazenyl]benzaldehyde and 4-benzyloxyanilinehydrochloride in ethyl alcohol solution. These mononuclear Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) complexes of the ligand were prepared and their structures were proposed by elemental analysis, and infrared and ultraviolet-visible spectroscopy; the proton NMR spectrum of the mbH ligand was also recorded. The azo-azomethine ligand, mbH, behaves as a bidentate ligand coordinating through the nitrogen atom of the azomethine (--CH=N--) and the oxygen atom of the phenolic group. Elemental analyses indicated that the metal:ligand ratio was 1:2 in the metal chelates. Powder X-ray diffraction parameters suggested a monoclinic system for the mbH ligand and its Ni(II), Cu(II), Co(II), and Zn(II) complexes, and an orthorhombic system for the Mn(II) complex. Electrochemical properties of the ligand and its metal complexes were investigated in 1 \times 10-3--1 \times 10-4 M DMF and CH3CN solvent in the range 200, 250, and 500 mV s-1 scan rates. The ligand showed both reversible and irreversible processes at these scan rates. In addition, genotoxic properties of the ligand and its complexes were examined.

WOS: 000342449400013, Nanocrystalline Fe - 40at.% Al alloy powders were prepared by using a mechanical alloying (MA) process with a planetary high-energy ball mill. The structural and the morphological properties of the powders were investigated by means of X-ray diffraction (XRD), and scanning electron microscopy (SEM), respectively. A disordered Fe(Al) solid solution with bcc crystal structure was formed after 10 h of MA. Longer MA durations introduced ordering in the alloyed powders. The final crystallite size was found to be as small as 5 nm whereas the internal strain was found to reach a final value of 2.1%. Also, the lattice parameter quickly increased to a maximum value of 0.2926 nm at 30 h of MA, and then decreased to a value of 0.2873 at 80 h of MA. SEM results showed variations in the shapes and the sizes of the particles in the powders at different stages. Furthermore, the microhardness values were found to increase gradually with increasing MA time due to work hardening, grain refinement and solid-solution formation. Magnetic properties such as the saturation magnetization (Ms) and the coercive field (Hc) were calculated from the hysteresis loops, and the results are presented as functions of the MA time., TUBITAK-BIDEPTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [2218], The author (B. Avar) would like to thank the TUBITAK-BIDEP 2218 National Research Fellowship Programme.

WOS: 000347660000001, Cobalt(II) and copper(II) complexes of a novel Schiff base ligand containing two -N=N- chromophore groups, derived from the condensation of 2-hydroxy-5-[(E)-phenyldiazenyl]benzaldehyde with p-aminoazobenzene were synthesized and characterized by analytical and spectroscopic methods. The X-ray powder diffraction analysis was used to determine the unit cell parameters of the synthesized ligand and its metal complexes. Self-isomerization via intramolecular proton transfer was investigated by UV-Vis and theoretical calculations. The effect of solvent polarity on UV-Vis was examined. The electronic structures of compounds were also predicted with computational chemistry methods. Theoretical vibrational and electronic spectra of the metal complexes were obtained from these structures. Binding energies of the metal complexes were obtained by quantum chemical calculations. Upon irradiation the ligands and their metal complexes gave blue light. The (1a) azo-aldehyde and (2a) azo-azomethine ligands revealed quantum yields of 35 and 41% and their excited-state lifetimes were 326 and 3.86 ns, respectively. Decreases in photoluminescence intensity and quantum yield upon complexation with metal ions were noted. The thermal behavior to include activation energy (E), entropy (Delta S*), enthalpy (Delta H*) and Gibbs free energy change (Delta G*), using Coats-Redfern (CR) and Horowitz-Metzger (HM) methods, were examined. (C) 2014 Elsevier B.V. All rights reserved.

WOS: 000343613400028, A new tridentate azo-azomethine ligand, N'-[{2-hydroxy-5-[(4-nitrophenyl)diazenyl]phenl}methylidene]benzohydrazidemonohydrate, (sbH center dot H2O) (1), is prepared by condensation of benzohydrazide and 2-hydroxy-5-[(4-nitrophenyl)diazenyl]benzaldehyde (a) with treatment of a solution of diazonium salt of p-nitroaniline and 2-hydroxybenzaldehyde in EtOH. The five coordination compounds, [Co(sb)(2)]center dot 4H(2)O (2), [Ni(sb)(2)]center dot H2O (3), [Cu(sb)(2)]center dot 4H(2)O (4), [Zn(sb)(2)]center dot H2O (5) and [Cd(sb)(2)]center dot H2O (6) are prepared by reacting the Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) ions with the ligand. The structures of the compounds are elucidated from the elemental analyses data and spectroscopic studies. It is found the ligand acts as a tridentate bending through phenolic and carbonyl oxygens and nitrogen atom of the C=N- group similar to the most of salicylaldimines. Comparison of the infrared spectra of the ligand and its metal complexes confirm that azo-Schiff base behaves as a monobasic tridentate ligand towards the central metal ion with an ONO donor sequence. Upon complexation with the ligand, the Cd(II), and Zn(II) ions form monoclinic structures, while Co(II), Cu(ID and Ni(II) ions form orthorhombic structures. Quantum chemical calculations are performed on tautomers and its metal chelates by using DFT/B3LYP method. Most stable tautomer is determined as tautomer (la). The geometrical parameters of its metal chelates are obtained as theoretically. The NLO properties of tautomer (la) and its metal complexes are investigated. Finally, the ligand and its metal complexes are assessed for their genotoxicity. (C) 2014 Elsevier B.V. All rights reserved., Unit of Coordination of Scientific Research Projects, Kahramanmara Sutcu Imam University, Kahramanmaras, Turkey [2010/2-15YLS], This work was financially supported by the Unit of Coordination of Scientific Research Projects, Kahramanmara Sutcu Imam University, Kahramanmaras, Turkey (Project no: 2010/2-15YLS). Also, the authors wish to thank Prof. Dr. Vickie McKee, Department of Chemistry at Lougbrough University, Leichester, UK for 1H NMR measurements.

Elemental mixtures of Al, Cu, Fe powders with the nominal composition of Al70Cu20Fe10 were mechanically alloyed in a planetary ball mill for 80 h. Subsequent annealing of the as-milled powders were performed at 600-800 degrees C temperature range for 4 h. Structural characteristics of the mechanically alloyed Al70Cu20Fe10 powders with the milling time and the heat treatment were investigated by X-ray diffraction (XRD), differential scanning calorimeter (DSC) and differential thermal analysis (DTA). Mechanical alloying of the Al70Cu20Fe10 did not result in the formation of icosahedral quasicrystalline phase (i-phase) and a long time milling resulted in the formation of beta-Al(Cu,Fe) solid solution phase (beta-phase). The i-phase was observed only for short-time milled powders after heat treatment above 600 degrees C. The beta-phase was one of the major phases in the Al70Cu20Fe10 alloy. The w-Al7Cu2Fe1 phase (w-phase) was obtained only after heat treatment of the short-time milled and unmilled samples. The present investigation indicated that a suitable technique to obtain a large amount of quasicrystalline powders is to use a combination of short-time milling and subsequent annealing.

In the present investigation, we examined the i‐phase formation during Mechanical Alloying (MA) of Al70Cu20Fe10 elemental blend using X‐ray diffraction (XRD).

Structural characteristics and thermal behaviour of the conventionally solidified Al-Cu-Fe alloys with nominal compositions of Al(70)Cu(20)Fe(10), Al(65)Cu(20)Fe(15) and Al(63)Cu(25)Fe(12) were investigated by X-ray diffraction, scanning electron microscopy, and differential thermal analysis techniques. Results show that a single quasicrystalline phase forms in a conventionally solidified Al(65)Cu(20)Fe(15) alloy, being thermodynamically stable without phase transition up to the melting point. A cubic AlFe(Cu) solid solution, identified as beta phase, and a cubic AlCu(Fe) solid solution, identified as tau phase, were observed with quasicrystalline phase for Al(63)Cu(25)Fe(12) alloy. Conventional solidification of Al(70)Cu(20)Fe(10) alloy does not result in quasicrystalline phase formation. However, the formation of quasicrystalline phase in conventionally solidified Al(70)Cu(20)Fe(10) alloy was observed after additional annealing at elevated temperature. SEM micrographs for Al(70)Cu(20)Fe(10) and Al(63)Cu(25)Fe(12) alloys after annealing at 700 degrees C for 4 h revealed the formation of pentagonal dodecahedrons in the quasicrystalline phase, with an edge size of about 30 mu m.

This work investigated the quasicrystalline phase formation during heat treatment in the Al63Cu25Fe12 alloy prepared via mechanical alloying, starting from pure elemental powders. The mechanical alloying process was performed at a speed of 300 rpm for times up to 70 hours. The structural evolution of the mechanically alloyed Al63Cu25Fe12 powders at different stages of milling was examined by X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. The present results showed that mechanical alloying of the Al63Cu25Fe12 alloy did not result in the quasicrystalline icosahedral phase (i-phase). The long time milling resulted in the formation of an AlFe(Cu) solid solution identified as the beta-phase. In order to examine the structural changes with annealing temperature, the mechanically alloyed powders were heat treated at 600, 700 and 800 degrees C for 4 hours under vacuum. However, the formation of a quasicrystalline phase in the Al63Cu25Fe12 alloy was observed after additional annealing at elevated temperature. In the present work, quasicrystalline phase formation in both the as-milled and heat-treated powders is discussed in detail.