A NEW METHOD FOR THE DETERMINATION OF THE TOTAL STRUCTURE FACTOR OF AMORPHOUS MATERIALS BY ENERGY-DISPERSIVE X-RAY DIFFRACTION (VARIABLE λ-METHOD)

1985 ◽  
Vol 46 (C8) ◽  
pp. C8-131-C8-135
Author(s):  
G. Fritsch ◽  
A. E. Lee ◽  
C. N.J. Wagner
1983 ◽  
Vol 38 (10) ◽  
pp. 1093-1097 ◽  
Author(s):  
E. Nassif ◽  
P. Lamparter ◽  
B. Sedelmeyer ◽  
S. Steeb

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.


1983 ◽  
Vol 38 (10) ◽  
pp. 1098-1102
Author(s):  
E. Nassif ◽  
P. Lamparter ◽  
B. Sedelmeyer ◽  
S. Steeb

Abstract The structural results for molten Ni81B19 are compared with the structure of a metallic glass which can be obtained at the same composition by rapid quenching the melt within a melt spin equipment. Structural relationship exists between the molten and the amorphous state. This feature follows especially from a marked asymmetry of the second maximum of the structure factor obtained from the melts, to which corresponds the splitting up of the second maximum in the total structure factor of the amorphous specimen. With the Ni53B47- and the Ni43B57 -melts which don't belong to the concentration range of glass-forming Ni-B-melts no peculiarities in the range of the second maximum of the structure factor were observed.


2013 ◽  
Vol 46 (6) ◽  
pp. 1749-1754 ◽  
Author(s):  
P. Wadley ◽  
A. Crespi ◽  
J. Gázquez ◽  
M.A. Roldán ◽  
P. García ◽  
...  

Determining atomic positions in thin films by X-ray diffraction is, at present, a task reserved for synchrotron facilities. Here an experimental method is presented which enables the determination of the structure factor amplitudes of thin films using laboratory-based equipment (Cu Kα radiation). This method was tested using an epitaxial 130 nm film of CuMnAs grown on top of a GaAs substrate, which unlike the orthorhombic bulk phase forms a crystal structure with tetragonal symmetry. From the set of structure factor moduli obtained by applying this method, the solution and refinement of the crystal structure of the film has been possible. The results are supported by consistent high-resolution scanning transmission electron microscopy and stoichiometry analyses.


1976 ◽  
Vol 2 (2) ◽  
pp. 95-111 ◽  
Author(s):  
L. Gerward ◽  
S. Lehn ◽  
G. Christiansen

The use of energy-dispersive X-ray diffraction for quantitative determination of preferred orientations in polycrystalline specimens is analysed. The method is applied to determinations of rolling texture and fibre texture. The adaptability of the method to in situ studies is demonstrated by observations of texture changes simultaneous with the deformation of a specimen in a tension test.


2006 ◽  
Vol 524-525 ◽  
pp. 743-748 ◽  
Author(s):  
Alexander M. Korsunsky ◽  
Shu Yan Zhang ◽  
Daniele Dini ◽  
Willem J.J. Vorster ◽  
Jian Liu

Diffraction of penetrating radiation such as neutrons or high energy X-rays provides a powerful non-destructive method for the evaluation of residual stresses in engineering components. In particular, strain scanning using synchrotron energy-dispersive X-ray diffraction has been shown to offer a fast and highly spatially resolving measurement technique. Synchrotron beamlines provide best available instruments in terms of flux and low beam divergence, and hence spatial and measurement resolution and data collection rate. However, despite the rapidly growing number of facilities becoming available in Europe and across the world, access to synchrotron beamlines for routine industrial and research use remains regulated, comparatively slow and expensive. A laboratory high energy X-ray diffractometer for bulk residual strain evaluation (HEXameter) has been developed and built at Oxford University. It uses a twin-detector setup first proposed by one of the authors in the energy dispersive X-ray diffraction mode and allows simultaneous determination of macroscopic and microscopic strains in two mutually orthogonal directions that lie approximately within the plane normal to the incident beam. A careful procedure for detector response calibration is used in order to facilitate accurate determination of lattice parameters by pattern refinement. The results of HEXameter measurements are compared with synchrotron X-ray data for several samples e.g. made from a titanium alloy and a particulate composite with an aluminium alloy matrix. Experimental results are found to be consistent with synchrotron measurements and strain resolution close to 2×10-4 is routinely achieved by the new instrument.


1975 ◽  
Vol 30 (12) ◽  
pp. 1655-1660 ◽  
Author(s):  
Y. Waseda ◽  
S. Tamaki

Abstract X-ray diffraction patterns have been obtained from molten Te at 470, 520 and 570 °C. The heights of the peak maxima in the structure factor were much the same in contrast with those of typical molten metals such as sodium.Molten Tl-Te alloys have been studied by X-ray diffraction for the alloy compositions 25, 33.3, 50, 60 and 75 at% Te at 500 °C and at about 20 °C above the liquidus. The total structure factors for the 25 and 33.3 at% Te alloys were almost the same as that of pure Tl. This implies that the atomic arrangement of these molten alloys is very close to that of pure Tl. Although a drastic change is not found in the general form of the structure factor, the parameter of the range of local atomic order abruptly increases on passing from Tl2Te to more Te-rich alloys. The three partial structures were also evaluated from the observed X-ray intensities assuming that each partial structure is independent of the relative abundance of the constituent elements in the alloys.


1987 ◽  
Vol 105 ◽  
Author(s):  
Zenon Bochyński

AbstractTill now the only effective method of direct determination of structural parameters has been X-ray diffraction structural analysis. This method applied to crystalline materials has proved a great success and applied to noncrystalline substances like for example inorganic glasses, is becoming more and more successful.Beginning with the W. Ostwald proposition /1913/ carried out by W. Friedrich /1913/ and P. Debye /1915/ through the papers by B.E. Warren et al. /1934–1942/ or by E.A. Poray-Koshits et al. /1934–1942/ till the most recently published papers devoted to structural studies of noncrystalline /amorphous/ materials we follow a significant progress in technology and methodology of these studies.The resulting significant improvement to the accuracy of results yields much more accurate structural models of non-crystalline materials.


1987 ◽  
Vol 42 (5) ◽  
pp. 507-510 ◽  
Author(s):  
E. Bühler ◽  
P. Lamparter ◽  
S. Steeb

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.


Sign in / Sign up

Export Citation Format

Share Document