Observation of Precipitates in Aluminium Alloys by Sub-Micrometer Resolution Tomography Using Fresnel Zone Plate
An X-ray microtomography combined with hard X-ray imaging microscopy, that potentially has a spatial resolution of the order of 10 to 100 nm, has been applied to the three-dimensional observation of internal microstructural features in overaged Al-Ag alloys. A Fresnel zone plate is used as an objective with a magnification of 49.3 times. Imaging of resolution test patterns has indicated spatial resolutions of around 180 and 200 nm in the vertical and horizontal directions, respectively. This paper reports the first impression of the microstructural imaging by means of such a high-resolution imaging microtomography. Precipitate microstructures are readily observed and quantified in terms of volume fraction and orientation. Conventional microtomography with a simple projection geometry is also applied for comparison purpose at the highest resolution level currently available at a third generation synchrotron facility. It would appear that the present technique provides a unique potential to observe the 3-D geometry and spatial distribution of nanoscopic features inside samples that are several orders of magnitude thicker than thin-foil specimens for TEM observation.
W.J. Poole, M.A. Wells and D.J. Lloyd
H. Toda et al., "Observation of Precipitates in Aluminium Alloys by Sub-Micrometer Resolution Tomography Using Fresnel Zone Plate", Materials Science Forum, Vols. 519-521, pp. 1361-1366, 2006