TEM Observation of Metastable Phases in Aged Al-Mg-Ge Alloys

2010 ◽  
Vol 654-656 ◽  
pp. 930-933 ◽  
Author(s):  
Kenji Matsuda ◽  
Junya Nakamura ◽  
Keisuke Yamamoto ◽  
Tokimasa Kawabata ◽  
Yasuhiro Uetani ◽  
...  
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Relative Frequency ◽  
Metastable Phase ◽  
Metastable Phases ◽  
Aged Condition ◽  
Aging Behavior ◽  
X Ray ◽  
Transmission Electron ◽  
Electron Energy Loss

The purpose of study is to investigate aging behavior, crystal structures of metastable phase and relative frequency of metastable phases in aged Al-Mg-Ge and Al-Mg-Ge-Si alloys using high resolution transmission electron microscope (HRTEM), energy dispersive X-ray spectroscopy (EDS) and electron energy-loss spectroscopy (EELS). Every alloy included rod-shaped precipitate which is the same as the typical metastable pahse, ’, in Al-Mg-Si alloy. Except to Mg-rich alloys, the Type-A precipitate, which is a typical metastable phase in the excess Si type Al-Mg-Si alloys and popular at over aged condition, was confirmed as a large rod-shaped precipitates in those alloys. This behavior is probably depends on the ratio of Mg/Ge. Also, Mg, Si and Ge were detected from the ’-phase in Al-Mg-Ge-Si alloy by EELS. This means that the ’-phase in Al-Mg-Ge-Si alloy consists of these 3 elements including Si, not just Ge to form metastable Mg2Ge.

HRTEM Observation of Rod-Shape Precipitates in Al-Mg-Si-Ag Alloy Aged at 523 K

2007 ◽  
Vol 561-565 ◽  
pp. 243-246 ◽  
Author(s):  
Junya Nakamura ◽  
Kenji Matsuda ◽  
Yoshio Nakamura ◽  
Tatsuo Sato ◽  
Susumu Ikeno
Keyword(s):  
Crystal Structure ◽  
Electron Microscope ◽  
High Resolution ◽  
Electron Diffraction ◽  
Metastable Phase ◽  
X Ray ◽  
Β Phase ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Hrtem Observation

The purpose of this study is to identify the crystal structure of metastable phase in Ag added Al-Mg-Si alloy to compare the formation of β’-phases in Al-Mg-Si alloys without Ag, using images of high resolution transmission electron microscope (HRTEM), selected area electron diffraction (SAED) patterns and an energy dispersive X-ray spectroscopy (EDS). The result of SAED patterns and HRTEM images have been simulated and compared with images then SAED patterns obtained from actual precipitates. SAED patterns and HRTEM images obtained from metastable phase in the Ag added Al-Mg-Si alloy showed similar to those of β’-phase in Al-Mg-Si alloy without Ag and the lattice spacings changed because of the effect of Ag.

The Effect of Ag-Addition on Crystal Structure of β'-Phase in Al-Mg-Si Alloy

2006 ◽  
Vol 519-521 ◽  
pp. 511-514 ◽  
Author(s):  
Junya Nakamura ◽  
Kenji Matsuda ◽  
Yoshio Nakamura ◽  
Tatsuo Sato ◽  
Susumu Ikeno
Keyword(s):  
Crystal Structure ◽  
Electron Microscope ◽  
High Resolution ◽  
Metastable Phase ◽  
Ag Addition ◽  
X Ray ◽  
Β Phase ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Diffraction Patterns

The purpose of this study is identity the crystal structure of metastable phase in Ag added Al-Mg-Si alloy by comparing the β’-phases in Al-Mg-Si alloy without Ag, using images of high resolution transmission electron microscope (HRTEM), selected area electron diffraction patterns (SADPs) and an energy dispersive X-ray spectroscopy (EDS). The result of SADPs and HRTEM images have been simulated and compared with images and SADPs obtained from actual precipitates. SADPs and HRTEM images obtained from metastable phase in the Ag added Al-Mg-Si alloy showed similar to those of β’-phase in Al-Mg-Si alloy without Ag and had different lattice spacings because of the effect of Ag.

Crystal Structure of the β'-Phase in Al-Mg-Si-Ag Alloy

2007 ◽  
Vol 539-543 ◽  
pp. 837-841 ◽  
Author(s):  
Kenji Matsuda ◽  
Junya Nakamura ◽  
Yoshio Nakamura ◽  
Tatsuo Sato ◽  
Susumu Ikeno
Keyword(s):  
Crystal Structure ◽  
Electron Microscope ◽  
High Resolution ◽  
Metastable Phase ◽  
Careful Analysis ◽  
X Ray ◽  
Β Phase ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Diffraction Patterns

The crystal structure of metastable phase in Ag added Al-Mg-Si alloy was investigated by comparing the β’-phases in Al-Mg-Si alloy without Ag, using images of high resolution transmission electron microscope (HRTEM), selected area electron diffraction patterns (SADPs) and an energy dispersive X-ray spectroscopy (EDS). SADPs and HRTEM images obtained from metastable phase in the Ag added Al-Mg-Si alloy showed similar to those of β’-phase in Al-Mg-Si alloy without Ag and had different lattice spacings because of the effect of Ag. According to our careful analysis on obtained HRTEM images and SADPs, it includes more complicated crystal lattice of distorted hexagons.

High Spatial Resolution Compositional Analysis at Interfaces

1980 ◽  
Vol 38 ◽  
pp. 356-359
Author(s):  
John B. Vander Sande ◽  
Thomas F. Kelly ◽  
Douglas Imeson
Keyword(s):  
Electron Microscope ◽  
High Spatial Resolution ◽  
Compositional Analysis ◽  
Scanning Transmission Electron Microscope ◽  
Thin Specimen ◽  
X Ray ◽  
Volume Of Interest ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Electron Energy Loss

In the scanning transmission electron microscope (STEM) a fine probe of electrons is scanned across the thin specimen, or the probe is stationarily placed on a volume of interest, and various products of the electron-specimen interaction are then collected and used for image formation or microanalysis. The microanalysis modes usually employed in STEM include, but are not restricted to, energy dispersive X-ray analysis, electron energy loss spectroscopy, and microdiffraction.

Experimental verification of the need for either jj or intermediate coupling in the 5f states of plutonium

2003 ◽  
Vol 802 ◽  
Author(s):  
K. T. Moore ◽  
M. A. Wall ◽  
A. J. Schwartz ◽  
B. W. Chung ◽  
J. G. Tobin ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Electron Microscope ◽  
Synchrotron Radiation ◽  
Single Phase ◽  
High Spatial Resolution ◽  
Intermediate Coupling ◽  
X Ray ◽  
Transmission Electron ◽  
Electron Energy Loss ◽  
X Ray Absorption

ABSTRACTHere, we demonstrate the power of electron energy-loss spectroscopy (EELS) in a transmission electron microscope (TEM) to investigate the electronic structure plutonium. Using EELS, TEM, and synchrotron-radiation-based X-ray absorption spectroscopy (XAS), we provide the first experimental evidence that Russell-Saunders (LS) coupling fails for the 5f states of Pu. These results support the assumption that only the use of jj or intermediate coupling is appropriate for the 5f states of Pu. EELS experiments were performed in a TEM and are coupled with image and diffraction data, therefore, the measurements are completely phase specific. It is shown that EELS in a TEM may be used to circumvent the difficulty of producing single-phase or single-crystal samples due to its high spatial resolution.

Synthesis of one-dimensional structured metal phthalocyanine in an ionic liquid

2007 ◽  
Vol 11 (10) ◽  
pp. 713-718 ◽  
Author(s):  
David S. Jacob ◽  
Somashekarappa Mallenahalli ◽  
Aharon Gedanken ◽  
Leonid A. Solovyov ◽  
Evangelia Xenogiannopoulou ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Electron Microscope ◽  
High Resolution ◽  
High Yield ◽  
Metal Phthalocyanine ◽  
X Ray Diffraction ◽  
One Dimensional ◽  
X Ray ◽  
Nickel Phthalocyanine ◽  
Transmission Electron

Nickel phthalocyanine is synthesized in an ionic liquid (1-butyl-3-methylimidazolium tetrafluoroborate) giving a high yield of one-dimensional structures. The morphology of the synthesized material is detected by a high-resolution scanning electron microscope, a high-resolution transmission electron microscope, characterized by powder X-ray diffraction, and a CHN analyzer. The nonlinear optical properties of the synthesized phthalocyanine are also investigated.

scholarly journals MicroED: a versatile cryoEM method for structure determination

2018 ◽  
Vol 2 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Brent L. Nannenga ◽  
Tamir Gonen
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Electron Diffraction ◽  
Structure Determination ◽  
Materials Science ◽  
Electron Diffraction Data ◽  
Determination Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron

Micro-electron diffraction, or MicroED, is a structure determination method that uses a cryo-transmission electron microscope to collect electron diffraction data from nanocrystals. This technique has been successfully used to determine the high-resolution structures of many targets from crystals orders of magnitude smaller than what is needed for X-ray diffraction experiments. In this review, we will describe the MicroED method and recent structures that have been determined. Additionally, applications of electron diffraction to the fields of small molecule crystallography and materials science will be discussed.

scholarly journals Synthesis and high-resolution structural and chemical analysis of iron-manganese-oxide core-shell nanocubes

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Aladin Ullrich ◽  
Mohammad Mostafizar Rahman ◽  
Paolo Longo ◽  
Siegfried Horn
Keyword(s):  
High Resolution ◽  
Core Shell ◽  
Bright Field ◽  
X Ray ◽  
The Core ◽  
Transmission Electron ◽  
High Boiling Solvent ◽  
Iron Manganese ◽  
Electron Energy Loss ◽  
Shell Region

AbstractWe have investigated the structure and chemical composition of nanoparticles synthesized by thermal decomposition of a mixture of iron oleate and manganese oleate in a high-boiling solvent in the presence of Na-oleate and oleic acid as surfactants by analytical transmission electron microscopy (TEM). The particles appear core-shell like in bright field TEM images. Higher spatial resolution TEM (HRTEM) analysis reveals a FeO/MnO like structure in the core and a spinel like structure in the shell. With high-resolution analytical methods like energy dispersive x-ray spectroscopy (EDS) and electron energy loss spectroscopy (EELS), the distribution of the metals Mn and Fe was investigated. Differences in the oxidation state of these metals were found between the core and the shell region. The presence of sodium from the used surfactant (Na-oleate) on the surface of the particles has been proved.

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