| Abstract
| - The orientation distributions of α-Al2O3 textured ceramics are determined from neutron diffractionspectra. A curved position-sensitive detector coupled to a tilt angle (χ) scan allowed the whole diffractionpattern treatment in the combined Rietveld−WIMV−Popa algorithm. Four textured alumina ceramicswere prepared by slip-casting under a high magnetic field and sintered at 800, 1300, 1400, and 1600 °C.The calculation of the distribution density, correlated to the representation of the normal and inversepole figures, highlights the influence of the magnetic field and sintering temperature on the texturedevelopment. The principal pole figures show a pronounced (00l) texture: (001) pole parallel to thedirection of slip-casting, and (110) pole with higher distribution density for the directions perpendicularto the expected fiber axis. The inverse pole figures calculated for the fiber direction show a major (001)component for all the samples. With the increasing sintering temperature, the texture strength is enhancedand the c-axis distribution is sharper. The effectiveness of the approach for determining the crystallitesize is also evident. As a global trend, the calculated crystallite size and observed grain size are similarand increase with the increasing sintering temperature. The mechanism of the texture development in thesintered specimens is certainly initiated from the preferred orientation of the green body after slip-castingunder a high magnetic field. The basal texture is enhanced during sintering by selective anisotropic graingrowth. We evidenced here the powerfulness of the Rietveld texture analysis to provide a basis for thecorrelation of texture, microstructural parameters, and anisotropic properties.
- Experimental and refined neutron diffraction patterns of α-Al203 textured ceramics as 0 to 90° χ-scans. Experiments were operated at the D1B line (ILL, Grenoble) with the curved position sensitive detector and the eulerian cradle. A significant (00l) texture is observed.
|
