Kinetics of cyclically-induced mechanical twinning in γ-TiAl unveiled by a combination of acoustic emission, neutron diffraction and electron microscopy

2021 ◽  
pp. 116921
Author(s):  
A. Vinogradov ◽  
M. Heczko ◽  
V. Mazánová ◽  
M. Linderov ◽  
T. Kruml
Keyword(s):  
Electron Microscopy ◽  
Acoustic Emission ◽  
Neutron Diffraction ◽  
Mechanical Twinning ◽  
Kinetics Of

A study of oxygen and vacancy ordering in YBa2Cu3O7−x

1989 ◽  
Vol 47 ◽  
pp. 164-165
Author(s):  
Y. P. Lin ◽  
A. H. O’Reilly ◽  
J. E. Greedan ◽  
M. Post
Keyword(s):  
Electron Microscopy ◽  
Neutron Diffraction ◽  
Oxygen Content ◽  
Carbon Film ◽  
Nitrogen Atmosphere ◽  
Vacancy Ordering ◽  
Powder Samples ◽  
Vacancy Chains ◽  
Chain Ordering

In the basal planes of the orthorhombic YBa2Cu3O7-X compound with x=0.07, which has a Tc of around 90K, chains of copper-oxygen are formed along the [010] direction. Previous investigations on the variation of Tc with oxygen content have shown the existence of a plateau at Tc = 60K for x=0.3 to 0.4, suggesting the presence of a separate phase. This phase has also been identified to be orthorhombic, but with a 2x superlattice along [100] of the parent structure, and the superlattice has been attributed to the formation of alternating copper-oxygen and copper-vacancy chains. In our work, we have studied the chain ordering phenomenon by electron microscopy and neutron diffraction on samples with different oxygen contents. We report here some of our electron microscopy findings for samples with x=0.4.Powder samples of YBa2Cu3O7-X were prepared by controlled re-oxidation of previously reduced material. For electron microscopy, the sample was dry ground using a mortar and pestle in a dry nitrogen atmosphere without the use of any solvent and transferred dry onto holey carbon film for examination in a Philips CM12 microscope.

Dynamic Transformation of Austenite at Temperatures above the Ae3

2018 ◽  
Vol 941 ◽  
pp. 633-638
Author(s):  
John Joseph Jonas ◽  
Clodualdo Aranas Jr. ◽  
Samuel F. Rodrigues
Keyword(s):  
Electron Microscopy ◽  
Driving Force ◽  
Energy Difference ◽  
Accelerated Cooling ◽  
Free Energy Difference ◽  
Dynamic Transformation ◽  
Plate Rolling ◽  
Temperature Transformation ◽  
Mn Steel ◽  
Kinetics Of

Under loading above the Ae3 temperature, austenite transforms displacively into Widmanstätten ferrite. Here the driving force for transformation is the net softening during the phase change while the obstacle consists of the free energy difference between austenite and ferrite as well as the work of shear accommodation and dilatation during the transformation. Once the driving force is higher than the obstacle, phase transformation occurs. This phenomenon was explored here by means of the optical and electron microscopy of a C-Mn steel deformed above their transformation temperatures. Strain-temperature-transformation (STT) curves are presented that accurately quantify the amount of dynamically formed ferrite; the kinetics of retransformation are also specified in the form of appropriate TTRT diagrams. This technique can be used to improve the models for transformation on accelerated cooling in strip and plate rolling.

scholarly journals Preparation and Assessment of Some Characteristics of Nanoparticles Based on Sodium Alginate, Chitosan, and Camellia chrysantha Polyphenols

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Phu Hoang Luong ◽  
Thuy Chinh Nguyen ◽  
The Dan Pham ◽  
Do Mai Trang Tran ◽  
Thi Ngoc Lien Ly ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Release Kinetics ◽  
Release Kinetic ◽  
Ionic Gelation ◽  
Visible Spectroscopy ◽  
Polyphenol Content ◽  
Release Process ◽  
Kinetics Of ◽  
Scanning Electron

This paper presents the characteristics, morphology, and properties of alginate/chitosan/polyphenol nanoparticles, in which polyphenols were extracted from Camellia chrysantha leaves collected in Tam Dao district, Vinh Phuc province (Vietnam). The alginate/chitosan/polyphenol nanoparticles were prepared by ionic gelation method at different polyphenol content. The characteristics and morphology of these nanoparticles were investigated using infrared spectroscopy (IR), ultraviolet-visible spectroscopy (UV-Vis), and scanning electron microscopy (SEM). Release kinetic of polyphenols from the alginate/chitosan/polyphenol nanoparticles was conducted in simulated human body fluids. The release kinetics of polyphenols from the above nanoparticles were also evaluated and discussed. The experimental results showed that the release process of polyphenols from the nanoparticles was dependent on three factors: time, pH of solution, and amount of polyphenols.

scholarly journals Kinetics of CxNy formation on electrode surface using the electrochemical method

2008 ◽  
Vol 40 (2) ◽  
pp. 147-154
Author(s):  
A. Chekhovskii ◽  
T. Tomila ◽  
A. Ragulya ◽  
I. Timofeeva ◽  
A. Ivanchuk ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Ir Spectroscopy ◽  
Electrode Material ◽  
Electrode Surface ◽  
Electrochemical Method ◽  
Deposition Process ◽  
Absorption Bands ◽  
X Ray ◽  
Kinetics Of ◽  
Electrolysis Products

Powded CxNy coatings were deposited from acetonitrile on Ni, Si, and C surfaces at a voltage 500-2000 V by the electrochemical method. Electrolysis products were analyzed by IR spectroscopy, X-ray phase analysis and electron microscopy. According to FTIR data, at frequencies 1370 and 1530 cm-1, absorption bands characteristic for stretching C-N and C=N oscillations are observed. The obtained results indicate that the deposition process occurs in a different manner in each specific case, i.e., the kinetics of the electrode depends on the electrode material (Ni, Si, and C).

Growth kinetics of CoSi2 and Ge islands observed with in situ transmission electron microscopy

Micron ◽  
1999 ◽  
Vol 30 (1) ◽  
pp. 21-32 ◽  
Author(s):  
F.M. Ross ◽  
P.A. Bennett ◽  
R.M. Tromp ◽  
J. Tersoff ◽  
M. Reuter
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Growth Kinetics ◽  
Transmission Electron ◽  
Kinetics Of
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