Microstructural Characterization of Long-Period Stacking Ordered Phases in Mg97Zn1Y2 (at.%) Alloy

2013 ◽  
Vol 19 (6) ◽  
pp. 1575-1580 ◽  
Author(s):  
Xiaohong Shao ◽  
Huajie Yang ◽  
Jeff T.M. De Hosson ◽  
Xiuliang Ma
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Diffraction ◽  
Point Group ◽  
Lattice Parameter ◽  
Space Group ◽  
Lpso Phase ◽  
Long Period ◽  
Transmission Electron

AbstractTransmission electron microscopy characterization of two major long-period stacking ordered (LPSO) phases in Mg–Zn–Y alloy, i.e., 18R- and 14H-LPSO are reported. The space group and atomic-scale microstructures of both compounds were determined using a combination of electron diffraction, convergent beam electron diffraction, high-resolution transmission electron microscopy, and Z-contrast scanning transmission electron microscopy. The 18R-LPSO phase is demonstrated to have a point group and space group 3m and R3m (or 3m and R3m), with the lattice parameter a = 1.112 nm and c = 4.689 nm in a hexagonal coordinate system. The 14H-LPSO phase has a point group 6/mmm and a space group P63 /mmc, and the lattice parameter is a = 1.112 nm and c = 3.647 nm. In addition, insertion of extra thin Mg platelets of several atomic layers, results in stacking faults in the LPSO phase. These results may shed some new light on a better understanding of the microstructure and deformation mechanisms of LPSO phases in Mg alloys.

Characterization of submicrometer fluid Inclusions in minerals by Analytical/Transmission Electron Microscopy and electron diffraction

1990 ◽  
Vol 48 (4) ◽  
pp. 424-424
Author(s):  
George Guthrie ◽  
David Veblen
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Microscope ◽  
Electron Diffraction ◽  
Light Microscopy ◽  
Fluid Inclusions ◽  
Energy Dispersive Spectrometer ◽  
Analytical Transmission Electron Microscopy ◽  
Transmission Electron

The nature of a geologic fluid can often be inferred from fluid-filled cavities (generally <100 μm in size) that are trapped during the growth of a mineral. A variety of techniques enables the fluids and daughter crystals (any solid precipitated from the trapped fluid) to be identified from cavities greater than a few micrometers. Many minerals, however, contain fluid inclusions smaller than a micrometer. Though inclusions this small are difficult or impossible to study by conventional techniques, they are ideally suited for study by analytical/ transmission electron microscopy (A/TEM) and electron diffraction. We have used this technique to study fluid inclusions and daughter crystals in diamond and feldspar.Inclusion-rich samples of diamond and feldspar were ion-thinned to electron transparency and examined with a Philips 420T electron microscope (120 keV) equipped with an EDAX beryllium-windowed energy dispersive spectrometer. Thin edges of the sample were perforated in areas that appeared in light microscopy to be populated densely with inclusions. In a few cases, the perforations were bound polygonal sides to which crystals (structurally and compositionally different from the host mineral) were attached (Figure 1).

Structural characterization of SmMn2GeO7 single microcrystals by electron microscopy

2005 ◽  
Vol 61 (1) ◽  
pp. 11-16 ◽  
Author(s):  
E. A. Juarez-Arellano ◽  
J. M. Ochoa ◽  
L. Bucio ◽  
J. Reyes-Gasga ◽  
E. Orozco
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Structural Characterization ◽  
Point Group ◽  
Spherical Mirror ◽  
Quaternary Compound ◽  
Cell Parameters ◽  
Transmission Electron ◽  
Electron Energy Loss

Single microcrystals of the new compound samarium dimanganese germanium oxide, SmMn2GeO7, were grown using the flux method in a double spherical mirror furnace (DSMF). The micrometric crystals were observed and chemically analysed with scanning electron microscopy (SEM) and X-ray energy dispersive spectroscopy (EDX). The structural characterization and chemical analysis of these crystals were also carried out using transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM), together with electron-energy-loss spectroscopy (EELS). We found that the new quaternary compound crystallizes in the orthorhombic system with the point group mmm (D 2h ), space group Immm (No. 71) and cell parameters a = 8.30 (10), b = 8.18 (10), c = 8.22 (10) Å and V = 558.76 Å3.

Characterization Of APB's In GaP

1996 ◽  
Vol 442 ◽  
Author(s):  
Dov Cohen ◽  
C. Barry Carter
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Diffraction ◽  
Convergent Beam Electron Diffraction ◽  
Antiphase Boundaries ◽  
Beam Electron ◽  
Transmission Electron ◽  
Convergent Beam ◽  
Crystallographic Orientations

AbstractAntiphase boundaries in GaP crystals epitactically grown on Si (001) have been characterized using transmission electron microscopy. Convergent-beam electron diffraction was used to identify the antiphase-related grains. The antiphase boundaries were observed to adopt facets parallel to specific crystallographic orientations. Furthermore, stacking-fault-like contrast was observed along the interface suggesting that the domains may be offset from one another by a rigid-body lattice translation.

Structure Analysis of a Long Period Stacking Ordered Phase in Mg-Al-Gd Alloys

2011 ◽  
Vol 1295 ◽  
Author(s):  
Hideyuki Yokobayashi ◽  
Kyosuke Kishida ◽  
Haruyuki Inui ◽  
Michiaki Yamasaki ◽  
Yoshihito Kawamura
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Dark Field ◽  
Ternary Alloys ◽  
Lpso Phase ◽  
Long Period ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Annular Dark Field ◽  
Structural Blocks

ABSTRACTCrystal structure of a long period stacking ordered (LPSO) phase newly found in Mg-Al-Gd ternary alloys was investigated by scanning transmission electron microscopy (STEM) and transmission electron microscopy (TEM). The Mg-Al-Gd LPSO phase was confirmed to be constructed with 6-layer structural blocks, which is similar to the case of the 18R-type LPSO phases in the other Mg-TM-RE alloys. Atomic resolution high-angle annular dark-field (HAADF) STEM imaging revealed that Gd atoms are enriched in four layers instead of two layers and are ordered in a long range within the 6-layer structural block.

scholarly journals Transmission electron microscopy as an important tool for characterization of zeolite structures

2018 ◽  
Vol 5 (11) ◽  
pp. 2836-2855 ◽  
Author(s):  
W. Wan ◽  
J. Su ◽  
X. D. Zou ◽  
T. Willhammar
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Electron Diffraction ◽  
Electron Tomography ◽  
Structure Characterization ◽  
Transmission Electron ◽  
High Resolution Tem

This review presents various TEM techniques including electron diffraction, high-resolution TEM and scanning TEM imaging, and electron tomography and their applications for structure characterization of zeolite materials.

Precipitation of Kr In Ni at Room Temperature

1986 ◽  
Vol 74 ◽  
Author(s):  
R. C. Birtcher ◽  
A. S. Liu
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Diffraction ◽  
Electron Scattering ◽  
Room Temperature ◽  
Lattice Parameter ◽  
Dark Field ◽  
Asymptotic Limit ◽  
Transmission Electron ◽  
Fluence Dependence

AbstractThe fluence dependence of Kr precipitation in Ni at room temperature has been studied with the aid of Transmission Electron Microscopy. As in other metals, the Kr precipitates in small cavities. Electron diffraction demonstrates that the Kr precipitates are solid, fcc crystals aligned with each other and the Ni lattice. The trends are similar to those observed for Kr precipitation in Al at room temperature. The average Kr lattice parameter, determined from the electron diffraction, increases with increasing Kr fluence from 0.515 nm to an asymptotic value of 0.545 nm. The asymptotic limit is due to the melting of the larger Kr precipitates. The mismatch between the Kr and Ni lattices is as large as 55%. Diffuse electron scattering was observed from large, liquid Kr precipitaes. This occurs for Kr fluences above 5.1020 Kr+ m-2 in Ni and above 2.5.1020 Kr+ m-2 in Al. At room temperature, the largest solid Kr precipitate observed in dark field images was 8.3 nm in diameter compared to 4.7 nm in Al. The larger precipitates are liquid or gas. The solid Kr metals at the same lattice parameter in both Ni and Al suggesting that the melting is thermodynamic in nature and independent of the host material.

Sign in / Sign up

Export Citation Format

Share Document