Electron-Diffraction Study on an Amorphous Al-V Alloy Produced by Electron Irradiation of Quasicrystalline Al-16 at-%V

1987 ◽  
Vol 42 (2) ◽  
pp. 113-119 ◽  
Author(s):  
J. Mayer ◽  
K. Urban ◽  
J. Härle ◽  
S. Steeb
Keyword(s):  
Electron Diffraction ◽  
Electron Irradiation ◽  
Pair Correlation ◽  
Amorphous State ◽  
Electron Diffraction Study ◽  
Voltage Electron ◽  
Total Structure Factor ◽  
Temperature Electron ◽  
Coordination Spheres ◽  
Total Structure

Quasicrystalline Al-16 at-%V was transformed to the amorphous state by low-temperature electron irradiation in a high-voltage electron microscope. Electron diffraction experiments were carried out in the amorphous state and in the crystalline state obtained after subsequent heat treatment. From the results the total structure factor was determined. The pair correlation function was calculated which yields the radii of the different coordination spheres and the total coordination number. The results are discussed in terms of current topological models of the structure of metallic glasses.

A Low-Temperature Electron Microscopy and Electron Diffraction Study of La1.84Sr0.16CuO4

1987 ◽  
Vol 26 (Part 2, No. 10) ◽  
pp. L1714-L1717 ◽  
Author(s):  
Takashi Onozuka ◽  
Mamoru Omori ◽  
Makoto Hirabayashi ◽  
Yasuhiko Syono
Keyword(s):  
Electron Microscopy ◽  
Electron Diffraction ◽  
Low Temperature ◽  
Diffraction Study ◽  
Electron Diffraction Study ◽  
Temperature Electron

Metastable Structures in Quenched Cr-Ti and Electron Irradiated Cu-Ti Alloys

1989 ◽  
Vol 157 ◽  
Author(s):  
W. Sinkler ◽  
D.E. Luzzi
Keyword(s):  
Electron Diffraction ◽  
Amorphous Phase ◽  
Electron Irradiation ◽  
Structural Relaxation ◽  
Amorphous State ◽  
Eutectoid Temperature ◽  
Ti Alloys ◽  
Metastable Structures

ABSTRACTElectron diffraction and imaging are used to characterize and contrast the structures and microstructures of a metastable Cr-Ti phase formed after quenching and a metastable Cu-Ti phase formed during electron irradiation. In both phases, marked structural anisotropies are found which have characteristics common to both of these bcc-based materials. It has been reported in the literature that this quenched-in metastable Cr-Ti phase undergoes a spontaneous structural relaxation into the amorphous state during sub-eutectoid temperature anneals [1]. Despite the similarity of the present experiments to those reported in the literature, an amorphization transformation was not observed. It is argued that the amorphization of this material requires the stabilization of the amorphous phase by an impurity.

High–Resolution Low Energy Electron Diffraction Study of Surface Instabilities and Growth Dynamics

1991 ◽  
Vol 237 ◽  
Author(s):  
H.-N. Yang ◽  
J.-K. Zuot ◽  
K. Fang ◽  
T.-M. Lu ◽  
G.-C. Wang
Keyword(s):  
High Resolution ◽  
Electron Diffraction ◽  
Pair Correlation ◽  
Growth Dynamics ◽  
Electron Diffraction Study ◽  
Growth Front ◽  
Low Energy ◽  
Energy Electron ◽  
Low Energy Electron Diffraction ◽  
Low Energy Electron

ABSTRACTRecent advances in high–resolution low–energy electron diffraction (HRLEED) techniques have led to a new capability which provides both very high spatial and temporal resolutions to probe quantitatively the equilibrium and dynamical processes that occur on surfaces and growth fronts. These techniques are especially powerful when the surface or growth front contains atomic steps. Different distributions of steps give different surface atomic pair correlation functions and therefore different angular profile shapes in the diffraction pattern. Recent examples of quantitative HRLEED study of low index plane equilibrium roughening and preroughening transitions are presented. In the growth dynamics, both two–level and multilevel step structures are considered. Examples of the measurements of growth exponents and dynamics scaling are presented.

X-Ray Diffraction Study on the Structure of Molten MgxZn(100 -x)-Alloys

1987 ◽  
Vol 42 (5) ◽  
pp. 507-510 ◽  
Author(s):  
E. Bühler ◽  
P. Lamparter ◽  
S. Steeb
Keyword(s):  
Amorphous Alloy ◽  
Short Range ◽  
Short Range Order ◽  
Pair Correlation ◽  
Range Order ◽  
X Ray Diffraction ◽  
X Ray ◽  
Nearest Neighbours ◽  
Total Structure Factor ◽  
Total Structure

By means of X-ray diffraction in transmission the molten MgxZn(1oo-x)-alloys (x = 0, 8, 15, 30, 40, 50, 60, 70, 73, 80, 90, 100) were investigated and the total structure factor S (Q) , the total pair correlation function, the number of nearest neighbours as well as the atomic distances were evaluated. For 30 ≦ x ≦ 80 a premaximum in S (Q) was observed which is caused by chemical short range order. The comparison of the premaximum of the Mg70Zn30-melt with that of the corresponding amorphous alloy shows that within the melt the chemical short range order amounts to about 40% of that of the amorphous alloy.

Structure of Mn-Si-Melts by Means of X-Ray Diffraction

1983 ◽  
Vol 38 (10) ◽  
pp. 1093-1097 ◽  
Author(s):  
E. Nassif ◽  
P. Lamparter ◽  
B. Sedelmeyer ◽  
S. Steeb
Keyword(s):  
Structure Factor ◽  
Melt Spinning ◽  
Pair Correlation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Coordination Numbers ◽  
Glass Forming ◽  
Structure Factors ◽  
Total Structure Factor ◽  
Total Structure

Abstract The binary molten alloys Mn74Si26 and Mn33.5Si66.5 have been investigated by means of X-ray diffraction. The total structure factors as well as the total pair correlation functions were evaluated. The interatomic distances and total coordination numbers are given. The structural results for Mn74Si26 were compared to those for amorphous Mn74Si23P3 and for a tetrahedral packing model. A pronounced shoulder on the second maximum of the structure factor, which normally is characteristic for the curves obtained with amorphous substances was observed for the Mn74Si26 melt. With the Mn33.5Si66.5 melt, however, this feature cold not be observed. Since with this concentration no glass forming by melt spinning is possible, a correlation between the shape of the second maximum of a total structure factor and the glass forming ability of the corresponding melt is suggested.

Sign in / Sign up

Export Citation Format

Share Document