scholarly journals Physical and Structural Characterization of Monocrystalline Cu-13.7% Al-4.2% Ni Alloy Submitted to Thermo-Cyclical Treatments under Applied Loads

Metals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 219
Author(s):  
Lioudmila A. Matlakhova ◽  
Elaine C. Pereira ◽  
Serguey A. Pulnev ◽  
Carlos Y. Shigue ◽  
Natalia A. Palii
Keyword(s):  
Martensitic Transformations ◽  
Nominal Composition ◽  
Special Device ◽  
X Ray Diffraction ◽  
Experimental Conditions ◽  
Optimum Load ◽  
Ni Alloy ◽  
Complex Structural ◽  
Martensite Reorientation

Monocrystalline alloy with a nominal composition of Cu-13.7% Al-4.2% Ni (wt.%) that shows reversible martensitic transformations (RMTs) was studied. The alloy, manufactured by the “Memory Crystals Group” in Russia, was subjected to thermo-cyclical treatment (TCT) under tension within a range that included critical RMT temperatures. A special device was developed to perform TCTs (up to 500 cycles) and three different loads were applied: 0.11, 0.26, and 0.53 MPa. X-ray diffraction analysis, optical microscopy, differential calorimetry, and Vickers microhardness were involved in the alloy’s characterization. Under TCTs, the alloy displayed complex structural transformation, revealing the sequence of RMT, β1 ↔ R ↔ β′1 + γ′1; the involved phases were coherently precipitated but very sensitive to the experimental conditions. It was found that during TCTs (from 300 cycles) performed under optimum load (0.26 MPa), the processes of martensite reorientation, hardening, and stabilization of the structure were the most intensive thus leading to a reduction of RMT critical intervals and increased microhardness.

scholarly journals Characterization of ferrite nanoparticles for preparation of biocomposites

2017 ◽  
Vol 8 ◽  
pp. 1257-1265 ◽  
Author(s):  
Urszula Klekotka ◽  
Magdalena Rogowska ◽  
Dariusz Satuła ◽  
Beata Kalska-Szostko
Keyword(s):  
Chemical Method ◽  
Ferrite Nanoparticles ◽  
Chemical Activity ◽  
Nominal Composition ◽  
X Ray Diffraction ◽  
Wet Chemical Method ◽  
X Ray ◽  
Transmission Electron ◽  
Wet Chemical

Ferrite nanoparticles with nominal composition Me0.5Fe2.5O4 (Me = Co, Fe, Ni or Mn) have been successfully prepared by the wet chemical method. The obtained particles have a mean diameter of 11–16 ± 2 nm and were modified to improve their magnetic properties and chemical activity. The surface of the pristine nanoparticles was functionalized afterwards with –COOH and –NH2 groups to obtain a bioactive layer. To achieve our goal, two different modification approaches were realized. In the first one, glutaraldehyde was attached to the nanoparticles as a linker. In the second one, direct bonding of such nanoparticles with a bioparticle was studied. In subsequent steps, the nanoparticles were immobilized with enzymes such as albumin, glucose oxidase, lipase and trypsin as a test bioparticles. The characterization of the nanoparticles was acheived by transmission electron microscopy, X-ray diffraction, energy dispersive X-ray and Mössbauer spectroscopy. The effect of the obtained biocomposites was monitored by Fourier transform infrared spectroscopy. The obtained results show that in some cases the use of glutaraldehyde was crucial (albumin).

Dispersion of TiO2 Nanotubes in a Chitosan Matrix

MRS Advances ◽  
2018 ◽  
Vol 3 (63) ◽  
pp. 3805-3810
Author(s):  
B. Núñez Mendoza ◽  
S.R. Vasquez-García ◽  
N. Flores-Ramírez ◽  
J. L. Rico ◽  
L. Zamora Peredo ◽  
...  
Keyword(s):  
Electrochemical Anodization ◽  
Infrared Spectrometry ◽  
X Ray Diffraction ◽  
Experimental Conditions ◽  
Second Stage ◽  
Chitosan Matrix ◽  
Third Stage ◽  
Membrane Type ◽  
Titanium Foils

ABSTRACTThis work presents the synthesis and characterization of TiO2 nanotubes (NTT) with chitosan (CS). In a first stage, electrochemical anodization of titanium foils was used to generate NTT in a membrane-type arrangement. From these experiments, suitable experimental conditions were selected. In a second stage, the synthesized NTT were detached from the titanium foils by sonication. In the third stage, the detached NTT were dispersed in an acid solution containing CS in various concentrations. Finally, the nanotubes-chitosan (NTT/CS) samples were characterized by Scanning Electron Microscopy (SEM), X-ray diffraction (XRD), and Fourier Transform Infrared Spectrometry (FTIR). Our results showed that the NTT presented very regular tube morphology with -OH and Ti-O- functional groups on the surface. The interaction of NTT and chitosan was enhanced by increasing the time of contact during the synthesis of the titanium composites.

scholarly journals Microstructural Characterization of Multiphase Coatings Produced By Chemical Vapor Deposition

1989 ◽  
Vol 168 ◽  
Author(s):  
R. A. Lowden ◽  
K. L. More ◽  
T. M. Besmann ◽  
R. D. James
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Analytical Electron Microscopy ◽  
Chemical Vapor ◽  
Microstructural Characterization ◽  
X Ray Diffraction ◽  
Experimental Conditions ◽  
Analytical Electron ◽  
Scanning Transmission

AbstractChemical vapor deposition has been utilized to produce ternary, multiphase coatings of various compositions of silicon carbide (SiC) with Ti, Cr, and Mo. Thermodynamic calculations have been performed for a variety of experimental conditions in each system. Scanning, transmission and analytical electron microscopy, and X-ray diffraction techniques have been used to characterize the microstructures and to determine compositions.

scholarly journals THE ICOSAHEDRAL PHASE OF Al63Cu25Fe12 SYSTEM

2019 ◽  
Vol 28 (1) ◽  
pp. 51-56
Author(s):  
Anastazia Melnik ◽  
Luciano Nascimento
Keyword(s):  
Chemical Elements ◽  
Stoichiometric Composition ◽  
Icosahedral Phase ◽  
Quasicrystalline Phase ◽  
Nominal Composition ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ideal Composition ◽  
Diffraction Patterns

The present work aimed to characterize the microstructure of the icosahedral phase (quasicrystalline phase-ϕ) of the system with stoichiometric composition of the quasicrystal Al63Cu25Fe12. The ternary alloy with nominal composition of Al63Cu25Fe12 was processed by mechanical alloying (MA) as a viable solid state processing method for producing various metastable and stable quasicrystalline phases. The structural characterization of the obtained samples was performed by X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM), while the elemental composition of the chemical elements Al, Fe and Cu were determined by X-ray spectroscopy technique of dispersive energy (EDS). According to the results of XRD, the diffraction patterns of Al63Cu25Fe12 showed the presence of β-Al(Fe, Cu) and λ-Al13Fe4 phases coexist with the thermodynamic ϕ-phase quasicrystalline. Finally, elemental analysis indicates that during alloy synthesis there is little variation of the ideal composition. The results indicate that alloys with high percentage of icosahedral phase can be obtained by casting in the air.

Diamagnetic and structural characterization of orthorhombic high-temperature superconductors in the system Y–Ba–Cu–O

1987 ◽  
Vol 65 (9) ◽  
pp. 1145-1148 ◽  
Author(s):  
M. Raudsepp ◽  
F. C. Hawthorne ◽  
X. Z. Zhou ◽  
I. Maartense ◽  
A. H. Morrish ◽  
...  
Keyword(s):  
Oxygen Vacancies ◽  
Structure Refinement ◽  
High Temperature Superconductors ◽  
Meissner Effect ◽  
Nominal Composition ◽  
X Ray Diffraction ◽  
X Ray ◽  
Preparation Conditions ◽  
Square Planar

Ceramic samples of the 90 K superconductor with nominal composition YBa2Cu3O7−x were made under varying preparation conditions. Some samples have a narrow transition-temperature range of about 1.5 K and a 100% "ac Meissner effect" near 77 K. The magnetic losses below 85 K were much reduced in these samples. Rietveld structure refinement in space group Pmmm using powder X-ray diffraction data showed significant oxygen vacancies in the square-planar CuO2 chains parallel to the y axis in the y–z plane, and Cu disorder about the origin along the x axis. The sample with the superior superconducting properties has the formula YBa2Cu3O6.92.

Mechanical Spectroscopy Study on Cu53.5Zr42Al4.5 Alloy

2011 ◽  
Vol 312-315 ◽  
pp. 1233-1237
Author(s):  
Odila Florêncio ◽  
Paulo Sergio Silva ◽  
Fernando Henrique De Sá ◽  
Paulo Wilmar Barbosa Marques ◽  
Javier Andres Muñoz Chaves ◽  
...  
Keyword(s):  
Internal Friction ◽  
Amorphous Structure ◽  
Nominal Composition ◽  
X Ray Diffraction ◽  
Mechanical Spectroscopy ◽  
Temperature Function ◽  
X Ray ◽  
Casting Technique ◽  
Dsc Curves

This study consists of the characterization of the anelastic properties of a Bulk Metallic Glasses (BMG) by mechanical spectroscopy, which can be defined as an energy absorption technique. The equipment used was the acoustic elastometer system, the anelastic relaxation spectra were carried out with a heating rate of 1 K/min and vacuum better than 10-5 torr, in the temperature range of 300 K to 640 K. The amorphous sample studied, with nominal composition of Cu53.5Zr42Al4.5, was processed by skull push-pull casting technique in a rectangular cavity cooper mould. Differential scanning calorimeter (DSC) curves have evidenced the amorphous structure although the X-ray diffraction (XDR) pattern has indicated a heterogeneous microstructure with amorphous matrix and some metaestable nanocrystalline phases which have not been identified yet. The dynamical elastic modulus of this alloy (between 54 GPa and 58 GPa at room temperature) and internal friction patterns as temperature function implied an increase of the crystalline phase during the measurements. This effect was confirmed with new X-ray diffraction measurements after the internal friction experiments.

scholarly journals ICOSAHEDRAL PHASE OF Al65Cu25Fe15

2020 ◽  
Vol 4 (01) ◽  
pp. 1-14
Author(s):  
Luciano Nascimento
Keyword(s):  
Stoichiometric Composition ◽  
Icosahedral Phase ◽  
Quasicrystalline Phase ◽  
Nominal Composition ◽  
X Ray Diffraction ◽  
Ideal Composition ◽  
Diffraction Patterns ◽  
State Processing ◽  
The Ideal

The present work aimed to characterize the microstructure of the icosahedral phase (quasicrystalline phase-ϕ) of the system with stoichiometric composition of the quasicrystal Al65Cu25Fe15 . The ternary alloy with nominal composition of Al63Cu25Fe12 was processed by mechanical alloying (MA) as a viable solid state processing method for producing various metastable and stable quasicrystalline phases. The structural characterization of the obtained samples was performed by X-ray diffraction (XRD) and scanning electron microscopy (SEM), while the elemental composition was determined by dispersive energy spectroscopy (DES). The diffraction patterns of Al65Cu25Fe15 showed the presence of ω-Al7Cu2Fe , β-Al(Fe, Cu) and λ-Al13Fe4 phases that coexist with the thermodynamic quasicrystalline phase-ϕ. Finally, elemental analysis indicates that during alloy synthesis there is little variation of the ideal composition. The results indicate that alloys with high percentage of icosahedral phase can be obtained by casting in the air.

scholarly journals Small-angle scattering for beginners

2021 ◽  
Vol 54 (6) ◽  
Author(s):  
Cedric J. Gommes ◽  
Sebastian Jaksch ◽  
Henrich Frielinghaus
Keyword(s):  
Small Angle ◽  
Small Angle Scattering ◽  
X Rays ◽  
X Ray Diffraction ◽  
Experimental Conditions ◽  
Time Resolved ◽  
Characterization Methods ◽  
Angle Scattering

Many experimental methods are available for the characterization of nanostructures, but most of them are limited by stringent experimental conditions. When it comes to analysing nanostructures in the bulk or in their natural environment – even as ordinary as water at room temperature – small-angle scattering (SAS) of X-rays or neutrons is often the only option. The rapid worldwide development of synchrotron and neutron facilities over recent decades has opened unprecedented possibilities for using SAS in situ and in a time-resolved way. But, in spite of its huge potential in the field of nanomaterials in general, SAS is covered far less than other characterization methods in non-specialized curricula. Presented here is a rigorous discussion of small-angle scattering, at a technical level comparable to the classical undergraduate coverage of X-ray diffraction by crystals and which contains diffraction as a particular case.

Synthesis and Characterization of Topological Insulator Bi2Te3 Nanowires

2015 ◽  
Vol 645-646 ◽  
pp. 32-39
Author(s):  
Zhen Guo ◽  
Lan Lu ◽  
Jing Yun Wang ◽  
Ying Jie Xing
Keyword(s):  
Low Cost ◽  
Diffraction Field ◽  
Synthesis And Characterization ◽  
X Ray Diffraction ◽  
Facile Hydrothermal Method ◽  
Experimental Conditions ◽  
X Ray ◽  
Structure And Morphology ◽  
Transmission Electron

Bi2Te3 nanowires are prepared by a low-cost and facile hydrothermal method without any surfactant. The structure and morphology of the nanowires are characterized by X-ray diffraction, field emission scanning electron microscopy, and transmission electron microscope. The influences of experimental conditions on the products are investigated. The growth mechanism is proposed based on the experimental results. This work is promising for the synthesis of Bi2Te3 nanowires with less impurity.

Preparation and Characterization of Sr, Ba Filled Type-I Ge Clathrate Single Crystals

2007 ◽  
Vol 336-338 ◽  
pp. 896-899 ◽  
Author(s):  
Ke Feng Cai ◽  
L.C. Zhang ◽  
Q. Lei
Keyword(s):  
Single Crystals ◽  
Room Temperature ◽  
Nominal Composition ◽  
Type I ◽  
Vibrational Modes ◽  
X Ray Diffraction ◽  
X Ray ◽  
Optimum Synthesis ◽  
Good Agreement

Sr or Ba filled type-I Ge clathrate single crystals were prepared using high pure elemental Ga, Ge, and Sr or Ba as the starting materials, and Ga as a flux. Powder X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), differential scanning calorimeter (DSC) were used to characterize the crystals, respectively. The results show that large and well-crystallized single crystals can be prepared under optimum synthesis condition. The composition of the crystals is in good agreement with the nominal composition (M8Ga16Ge30, M=Sr, Ba). Raman spectra of the single crystals were studied at room temperature and several of the Raman active vibrational modes in the crystals have been identified.

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