Analysis of the asymptotic properties of X-ray line broadening caused by dislocations

Abstract

A new evaluation method and its application are discussed in detail for the determination of some important statistical parameters of a dislocation assembly, namely the average dislocation density, the average¯uctuation of the dislocation density and the average polarization, from the X-ray diffraction line pro®le. The method is based only on the analytical properties of the strain ®eld of dislocations, regardless of the actual form of the dislocation distribution, so it can also be applied to inhomogeneous dislocation structures. The applicability of the evaluation procedure is demonstrated for broadened Bragg peaks of deformed Cu single crystals and of nanocrystalline Cu produced by inert-gas condensation.

X-ray diffraction peak profiles from threading dislocations in GaN epitaxial films

“…is numerically calculated for different values of the parameter R. The curves merge at a common q −3 asymptotic that does not depend on R. 12,28,33,35 Then, Eq. (10) has an asympotic behavior (for ω large in comparison with the peak width) (13) for different values of the parameter R. All curves merge at a common q −3 asymptotic.…”

Defining recrystallization in pilgered Zircaloy-4: From preferred nucleation to growth inhibition

“…Dislocation density estimations from X-ray line profile analysis is an involved, albeit evolving, subject [1,[51][52][53][54][55]. In the present study, methodology described in [55] was used,…”

Substructure Analysis in Heavily Deformed Materialsby Diffraction Methods

“…A physically adequate treatment of the peak broadening due to such substructures was given in. [21,22,25,26] But the broadening can also be interpreted in terms of the composite model presented in, [27,28] considering the scattering crystal volume as an arrange-ment of thick cell walls with the volume fraction w CW and the mean total dislocation density r CW and the cell interiors with the volume fraction w CI = 1 ± w CW and the mean total dislocation density r CI . Accordingly, the observable X-ray reflections of the composite have to be treated as diffraction doublets, [23,24] whose components must be separated and evaluated via Eq.…”