Quantitative Texture Analysis with the HIPPO TOF Diffractometer
|
| Journal |
Materials Science Forum (Volumes 495 - 497) |
| Volume |
Textures of Materials - ICOTOM 14 |
| Edited by |
Paul Van Houtte and Leo Kestens |
| Pages |
113-118 |
| DOI |
10.4028/www.scientific.net/MSF.495-497.113 |
| Online since |
September, 2005 |
| Authors |
J. Pehl,
Siegfried Matthies,
H.R. Wenk,
Luca Lutterotti,
Sven C. Vogel
|
| Keywords |
Aluminum, Neutron Diffraction, ODF Analysis, Rietveld Method |
| Abstract |
One of the design goals of the neutron time-of-flight (TOF) diffractometer HIPPO (HIgh Pressure - Preferred Orientation) at LANSCE (Los Alamos Neutron Science Center) was efficient quantitative texture analysis. In this paper, the effects of the HIPPO detector geometry and layout on texture analysis, particularly the shape and dimensions of the detector panels, are investigated. An aluminum sample with a strong and asymmetric texture was used to determine the methodological limitations of various methods of quantitative texture analysis. Several algorithms for extracting the orientation distribution function (ODF) from the TOF-spectra are compared: discrete orientations at arbitrary positions, harmonic method in Rietveld codes (MAUD and GSAS) and discrete methods in MAUD. All methods provide a similar representation of the main texture component, but discrete methods have a fundamental advantage over harmonic methods in
characterizing regions of the ODF with low orientation densities. For HIPPO data of the present sample, harmonic expansions beyond lmax= 12 introduce subsidiary maxima and minima, which are consistently identified as artifacts. The results of our analysis establishes HIPPO as an efficient instrument to quantitatively determine preferred orientations in relatively short measuring times, if the texture features are not exceedingly sharp (full-width at half-maximum (FWHM) in the ODF > 20-30°). |
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