Microstructural Analysis of Hexagonal Close-Packed Metals Using X-Ray Diffraction and Transmission Electron Microscopy

1990 ◽  
Vol 209 ◽  
Author(s):  
M. Griffiths ◽  
J.E. Winegar

ABSTRACTThe techniques employed for X-ray diffraction analysis of dislocation substructures in hexagonal close-packed metals are descibed and assessed by comparison with direct observations using transmission electron microscopy.

1991 ◽  
Vol 35 (A) ◽  
pp. 593-599 ◽  
Author(s):  
M. Griffiths ◽  
J.E. Winegar ◽  
J.F. Mecke ◽  
R.A. Holt

AbstractX-ray diffraction (XRD) line-broadening analysis has been used to determine dislocation densities in zirconium alloys with hexagonal closepacked (hep) crystal structures and a complex distribution of dislocations reflecting the plastic, anisotropy of the material. The validity of the technique has been assessed by comparison with direct measurements of dislocation densities in deformed polycrystalline and neutron-irradiated single crystal material using transmission electron microscopy (TEM). The results show that-there is good agreement between the XRD and TEM for measurements on the deformed material whereas there is a large discrepancy for measurements on the irradiated single crystal; the XRD measurements significantly underestimating the TEM observations.


2001 ◽  
Vol 16 (7) ◽  
pp. 1960-1966 ◽  
Author(s):  
K. Miyazawa ◽  
H. Satsuki ◽  
M. Kuwabara ◽  
M. Akaishi

The structure and hardness of C60 bulk specimens compressed under 5.5 GPa at room temperature to 600 °C are investigated by high-resolution transmission electron microscopy, x-ray diffraction, and micro-Vickers hardness tests. A strong accumulation of the [1 1 0]tr orientation of high-pressure-treated C60 specimens was developed along the compression axis, and stacking faults and nano-sized deformation twins were introduced into the C60 specimens compressed at 450–600 °C. Curved lattice planes indicating a polymerization of C60 were observed by high resolution transmission electron microscopy (HRTEM). The polymerization of the high-pressure-compressed C60 is also supported by the computer simulation of HRTEM images.


Author(s):  
Е.В. Астрова ◽  
А.В. Парфеньева ◽  
А.М. Румянцев ◽  
В.П. Улин ◽  
М.В. Байдакова ◽  
...  

The effect of annealing temperature in argon atmosphere on the ability of Si-C nanocomposites to reversibly insert lithium was investigated. It was found that the higher the annealing temperature during the formation of the composite, the lower is the capacitance of the electrode made from it. X-ray diffraction analysis and transmission electron microscopy reveal that the reason of the capacitance decrease is formation at T  1100°C of silicon carbide of cubic modification -SiC, inactive with respect to the formation of lithium alloys or intercalates.


2001 ◽  
Vol 65 (23) ◽  
pp. 4385-4397 ◽  
Author(s):  
Tomoki Nakamura ◽  
Takaaki Noguchi ◽  
Toru Yada ◽  
Yoshihiro Nakamuta ◽  
Nobuo Takaoka

2021 ◽  
Author(s):  
Chen Yu Wu ◽  
Yi Xuan Lin ◽  
Jyun Yang Wang ◽  
Chia Hung Lee ◽  
Chung Yu Chiu ◽  
...  

Abstract Typically, Sn cannot be finished on Ni and Ag surfaces via the immersion process. In this work, through galvanic reaction, immersion Sn finish was processed on an immersion Ag finish coexisting with a Ni surface. Herein, the detailed mechanism of the reduction of Sn2+ ions on the immersion Ag surface through galvanic reaction is reported. Through transmission electron microscopy and X-ray diffraction analysis, the uncommon Ag4Sn phase, instead of the common Ag3Sn phase, was confirmed to form during the Sn immersion of the Ag immersion layer. The Ag4Sn phase was found to form between the Ag grains in the immersion Sn layer. The mixed Ag/Ag4Sn structure in the immersion Sn layer can be explained by the galvanic reaction. The preferred formation of the Ag4Sn during the Sn immersion of the Ag immersion layer is discussed from the viewpoint of thermodynamics. The changes in the Gibbs free energy of the formation of the Ag3Sn and Ag4Sn phases were calculated as −3.67 and −8.89 kJ/mol, respectively. This confirms that the Ag4Sn phase is the favorable phase formed in the immersion Sn over the immersion Ag layer.


Clay Minerals ◽  
1993 ◽  
Vol 28 (2) ◽  
pp. 243-253 ◽  
Author(s):  
V. Šucha ◽  
I. Kraust ◽  
H. Gerthofferová ◽  
J. Peteš ◽  
M. Sereková

AbstractThe conversion of smectite to illite has been studied in buried bentonites and shales of the East Slovak Neogene Basin, using X-ray diffraction analysis and transmission electron microscopy. A good correlation was observed in both rock types between the content of expandable layers in interstratified illite-smectite (I-S) minerals and burial depth (temperature), with shales from a given depth being markedly more illitic than bentonties. This difference disappeared at a depth of ~3 km, which represents a temperature of ~150°C The diameter of fundamental illite particles increased with decreasing expandability. Potassium fixation together with neoformation appear to be the mechanisms of conversion of smectite to illite.


Author(s):  
R. Gronsky

The phenomenon of clustering in Al-Ag alloys has been extensively studied since the early work of Guinierl, wherein the pre-precipitation state was characterized as an assembly of spherical, ordered, silver-rich G.P. zones. Subsequent x-ray and TEM investigations yielded results in general agreement with this model. However, serious discrepancies were later revealed by the detailed x-ray diffraction - based computer simulations of Gragg and Cohen, i.e., the silver-rich clusters were instead octahedral in shape and fully disordered, atleast below 170°C. The object of the present investigation is to examine directly the structural characteristics of G.P. zones in Al-Ag by high resolution transmission electron microscopy.


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