A synchrotron tomographic energy-dispersive diffraction imaging study of the aerospace alloy Ti 6246

Abstract

A titanium alloy sample (#6246) containing a linear friction weld has been imaged nondestructively using tomographic energy‐dispersive diffraction imaging (TEDDI). The diffraction patterns measured at each point of the TEDDI image permitted identification of the material and phases present (±5%). The image also showed the preferred orientation and size–strain distribution present within the sample without the need for any further sample preparation. The preferred orientation was observed in clusters with average dimensions very similar to the experimental spatial resolution (400 µm). The length scales and preferred orientation distributions were consistent with orientation imaging microscopy measurements made by Szczepanski, Jha, Larsen & Jones [Metall. Mater. Trans. A (2008), 39, 2841–2851] where the microstructure development was linked to the grain growth of the parent material. The use of a high‐energy X‐ray distribution (30–80 keV) in the incident beam reduced systematic errors due to the source profile, sample and air absorption. The TEDDI data from each voxel were reduced to an angle‐dispersive form and Rietveld refined to a mean χ2 of 1.4. The mean lattice parameter error (δd/d) ranged from ∼10−4 for the highly crystalline regions to ∼10−3 for regions of very strong preferred orientation and internal strain. The March–Dollase preferred orientation errors refined to an average value of ±2%. A 100% correlation between observed fluorescence and diffraction peak broadening was observed, providing further evidence for vicinal strain broadening.

Diffraction/scattering computed tomography for three-dimensional characterization of multi-phase crystalline and amorphous materials

“…1) (Harding et al, 1985(Harding et al, , 1987Kleuker et al, 1998). Using polychromatic Laue diffraction, two-and three-dimensional microscopy images have been successfully obtained on well crystallized thin films and alloys (Tamura et al, 2002;Budai et al, 2003;Larson et al, 2002;Beale et al, 2007;Cernik et al, 2011;Hofmann et al, 2012). Using monochromatic diffraction, it has been shown that three-dimensional images of well crystallized samples can also be reconstructed, on the basis of the diffracted beam paths of each grain (considered as single crystals).…”

Diffraction scattering computed tomography: a window into the structures of complex nanomaterials

“…51–53 Energy-dispersive diffraction tomography 54 has also been performed to track sulfate attack of Portland cement 55 and to study Ti alloys. 56 …”

New program with new approach for spectral data analysis

“…EasyDD has been used in a number of key studies such as [5, 7, 10--14]. It has also been used by the High Energy X-Ray Imaging Technology (HEXITEC) project for the development of multi-pixel 2D X-ray detectors [3,9,16]. However, in this section we present a brief account of a nickel chloride catalysis system study as a show case for the use of EasyDD in processing and analyzing powder diffraction data.…”