HRTEM Observation of the Age Hardening Precipitates in Mg-Gd-Sc Alloys, with Different Gd Concentrations

2011 ◽  
Vol 409 ◽  
pp. 335-338
Author(s):  
Takafumi Fujii ◽  
Kenji Matsuda ◽  
Tokimasa Kawabata ◽  
Susumu Ikeno
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Transmission Electron Microscope ◽  
Age Hardening ◽  
Number Density ◽  
Maximum Hardness ◽  
Β Phase ◽  
Transmission Electron ◽  
Hrtem Observation

High resolution transmission electron microscope (HRTEM) observations were performed to investigate the age hardening precipitates in Mg-Gd-Sc alloys. The maximum hardness of these alloys increased with Gd content. The precipitates with the features of β” phase and β’ phase in Mg-Gd alloy were observed in Mg-15Gd-6.4Sc and Mg-10Gd-6.4Sc alloys. Maximum hardness and number density of precipitate in Mg-15Gd-6.4Sc alloy were higher than that in Mg-10Gd-6.4Sc alloy, and the finer precipitates with higher number of density were contributed to the maximum hardness in Mg-Gd-Sc alloys.

HRTEM Observation of the Age Hardening Precipitates in Mg-Zn Alloy

2007 ◽  
Vol 26-28 ◽  
pp. 157-160
Author(s):  
Shogo Mori ◽  
Tokimasa Kawabata ◽  
Kenji Matsuda ◽  
Susumu Ikeno
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Early Stage ◽  
Age Hardening ◽  
Aged Specimen ◽  
Transmission Electron ◽  
Hrtem Observation ◽  
Peak Aged ◽  
Zn Alloy ◽  
Different Parts

The age hardening precipitates of Mg-4.7mass%Zn alloy aged at 423K,473K were studied by using high-resolution transmission electron microscope (HRTEM). Contrasts of mono layers were confirmed to exist on the (0001) and (1100) matrix planes. It was considered that the contrast of mono layer was plate-like shape, and identified as pre-precipitates from as-quenched stage to early stage of aging at 473K for 32h . In the peak aged specimen of aged at 473K, the β1’ phase was observed. The β1’ phase has a rod-like shape and parallel to c-axis of Mg matrix. It can be observed orientation relationship between Mg matrix and β1’phase has not only same parts to previous reports but also different parts in one β1’ phase .

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.

Crystal structure and defects of Zr4Co4Si7 (V-phase) investigated by high resolution transmission electron microscope

1997 ◽  
Vol 12 (2) ◽  
pp. 377-384
Author(s):  
J. F. Mao ◽  
H. Q. Ye ◽  
X. G. Ning ◽  
L. L. He ◽  
D. Z. Yang
Keyword(s):  
Crystal Structure ◽  
Electron Microscope ◽  
High Resolution ◽  
Transmission Electron Microscope ◽  
Phase Structure ◽  
Structure Type ◽  
Image Simulation ◽  
Transmission Electron ◽  
Hrtem Observation ◽  
Coherent Interfaces

The results of high resolution transmission electron microscope (HRTEM) observation and image simulation show that Zr4Co4Si7 possesses the same structure type of Zr4Co4Ge7. Addition of Fe or Ni into the Zr4Co4Si7 compound, except that the dimensions changed slightly, does not change the lattice type and coordination in the crystal structure, maintaining the V-phase structure. Also, twins with coherent boundaries and partially coherent interfaces are observed. The image conditions of Zr4Co4Si7 and the structure differences between Zr4Co4Si7 and tetrahedral close-packed phases are also discussed.

HRTEM Observation of the Precipitates in Heat-Resistant Mg-Gd-Y-Zr Alloy

2007 ◽  
Vol 539-543 ◽  
pp. 1769-1774 ◽  
Author(s):  
Tokimasa Kawabata ◽  
Yuya Fukuda ◽  
Kenji Matsuda ◽  
Shigeharu Kamado ◽  
Yo Kojima ◽  
...  
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Lattice Structure ◽  
Early Stage ◽  
Aged Specimen ◽  
Β Phase ◽  
Transmission Electron ◽  
Hrtem Observation ◽  
Peak Aged ◽  
Zr Alloy

The high resolution transmission electron microscope (HRTEM) observation was carried out to investigate the microstructure of precipitates in Mg-Gd-Y-Zr alloy. In the early stage of aging at 423K, monoatomic layers were observed along the (1 1 00)Mg plane. After 64h aging at 423K, the contrast of β” phase based on ordered D019 hexagonal super lattice structure was appeared. The monoatomic layers, two layers spaced by (1 1 00) Mg planes and β’ phase based on bco-structure were observed in the specimen aged for 128h. In the peak- aged specimen, the β’ phase and monoatomic layers were observed.

A New High Resolution Transmission Electron Microscope with Second-Zone Objective Lens

1969 ◽  
Vol 27 ◽  
pp. 176-177 ◽  
Author(s):  
H. Tochigi ◽  
H. Uchida ◽  
S. Shirai ◽  
K. Akashi ◽  
D. J. Evins ◽  
...  
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Transmission Electron Microscope ◽  
Objective Lens ◽  
High Excitation ◽  
Transmission Electron ◽  
New Instrument

A New High Excitation Objective Lens (Second-Zone Objective Lens) was discussed at Twenty-Sixth Annual EMSA Meeting. A new commercially available Transmission Electron Microscope incorporating this new lens has been completed.Major advantages of the new instrument allow an extremely small beam to be produced on the specimen plane which minimizes specimen beam damages, reduces contamination and drift.

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