The effect of dislocation contrast on x-ray line broadening: A new approach to line profile analysis

Abstract

The x-ray line profiles of an ultrafine grained copper crystal, produced by equal-channel angular pressing, were measured by a special high resolution diffractometer with negligible instrumental line broadening. The analysis of the line breadths and the Fourier coefficients have shown that taking into account the contrast caused by dislocations on line profiles gives new scaling factors in the Williamson–Hall plot and in the Warren–Averbach analysis, respectively. When strain is caused by dislocations the new procedure proposed here enables a straightforward determination of particle size and strain, the latter in terms of the dislocation density.

The effect of cooling rates on the microstructure and mechanical properties of thermo-mechanically processed Ti–Al–Mo–V–Cr–Fe alloys

“…Other factors such as dislocation density, slip activity [32], and the presence of stacking faults can also affect the shape and/or position of diffraction peaks [27]. Warren [39], Randle and Engler [40] developed the XRDLPA approach for the analysis of the microstructure, which was later followed by others [28,[41][42][43][44][45] with some modifications making it possible to determine the crystallite size and microstrain in materials reliably. Similarly to [16,23], the modified Rietveld [46] method has been used in order to characterise microstructures in this investigation.…”

Effect of the Surface Layer Strained by Mechanical Grinding on X-ray Diffraction Analysis

“…1,4,9) For the same X-ray diffractometer, instrumental effect is constant at critical diffraction angle. Therefore, the surface strain introduced by mechanical grinding could increase FWHM levels by enhancing both crystallite size and dislocations effects.…”

“…In general, qualitative illustrations on removing grinded surface by mechanical or/ and electrolytic polish were given. [3][4][5][6] But less quantitative results were shown. 4) In the present work, main attentions will be firstly paid on the strained layer on XRD analyses in ferritic steels.…”

“…[3][4][5][6] But less quantitative results were shown. 4) In the present work, main attentions will be firstly paid on the strained layer on XRD analyses in ferritic steels. The depth of damaged layer is to be quantitatively decided after grinding by various sander papers.…”

<b>X-ray Fourier Analysis on Rolling Contact Fatigue Layer Formed in Rail</b>

“…Equation (1) gives us both values of the crystallite size and strain through a monotonous function of K. Unfortunately, the steel consisting of Fe has strain anisotropy, which made it hard to analyze using a monotonous function [9]. Ungar et al adopted a combination of the dislocation contrast factor, C -and the magnitude of diffraction vector, K as a new scaling factor for suppressing strain anisotropy [5]. On the assumption that dislocation accounts for most of the contribution of the strain to the peak broadening, they proposed a modified Williamson-Hall equation as shown below.…”