Microstructure analysis using SAXS/USAXS techniques

Abstract

Introduction to small-angle X-ray scattering (SAXS) and ultra small-angle X-ray scattering (USAXS) is presented. SAXS is useful for microstructure analysis of age-hardenable alloys containing precipitates with several to several tens of nanometers in size. On the other hand, USAXS is appropriate to examine much larger microstructural heterogeneities, such as inclusions, voids, and large precipitates whose size is typically around one micrometer. Combining these two scattering methods, and sometimes also with diffractions, it is possible to assess the hierarchical structure of the samples insitu and nondestructively, ranging from phase identification, quantitative analysis of precipitation structures upto their mesoscopic aggregates, large voids and inclusions. From technical viewpoint, USAXS requires some specific instrumentation for its optics. However, once a reasonable measurement was made, the analysis for the intensity is the same as that for conventional SAXS. In the present article, short introduction of conventional SAXS is presented, and then, the analysis is applied for a couple of USAXS data obtained for well-defined oxide particles whose average diameters are expected to be about 0.3 micrometers.