Quantitative Rietveld texture analysis from single synchrotron diffraction images

Preferred orientation is immediately visible on synchrotron diffraction images as intensity variations along Debye rings. In this report, the Rietveld method is applied to obtain quantitative information about the orientation distribution from the analysis of a single synchrotron diffraction image. The method is illustrated for hexagonal cold-rolled zirconium, investigated in situ in a vacuum furnace with high-energy X-rays, both before and after the onset of recrystallization. Preferred orientation is immediately visible on synchrotron diffraction images as intensity variations along Debye rings. In this report, the Rietveld method is applied to obtain quantitative information about the orientation distribution from the analysis of a single synchrotron diffraction image. The method is illustrated for hexagonal cold-rolled zirconium, investigated in situ in a vacuum furnace with high-energy X-rays, both before and after the onset of recrystallization. With CCD cameras and image-plate recorders, synchrotron diffrac- tion images are increasingly used to document the presence of texture in a wide variety of materials, including metals, minerals and biological samples. While the presence of texture is immediately obvious, only a detailed analysis provides information about the orientation distribution function (ODF). In much of the earlier work on this subject, texture information was obtained by imposing axial sample symmetry, by combining images obtained in different sample orientations, or by rotating the sample during an exposure. These methods are cumbersome and often not possible owing to geometric constraints or if the sample undergoes changes with time. Thus, a method that relies on single images would be highly desirable. Indeed, it has recently been shown that intensity variations along several Debye rings contain sufficient information to determine the ODF, without imposing any sample symmetry, both for cubic and for hexagonal materials. Intensity variations along Debye rings were extracted from the images and used for texture computation. In this report, we are advancing the approach by applying the Rietveld method directly to two-dimensional images, such as those shown for rolled and recrystallized zirconium.