2019 Volume 58 Issue 1 Pages 103-108
Recently, due to the increase of experiments using synchrotron X–rays, the studies of precipitates by SAXS（Small angle X–ray scattering） measurement with high energy X–ray are also increasing. Although a scattering profile measured from metallic materials contains information about the size, shape and number density of precipitates, only precipitate size was evaluated with a spherical shape approximation in a number of studies using the SAXS method. There is little investigation of precipitation morphology from SAXS profiles. In this study, the SAXS measurements with synchrotron high energy X–ray of three kinds of Cu alloys, which are including various sizes and shapes of precipitates, were carried out. The fitting analysis using the local monodisperse approximation with the most appropriate form factor was adopted to estimate the size and shape of precipitates. These results were compared to the values analyzed by previous TEM observations. The sizes of Fe precipitates with a spherical shape and Co–Fe precipitates which changes from sphere to rectangular plate–like form via cuboid were accurately calculated by the local monodisperse approximation with the form factor of a sphere. On the other hand, Ni2Si precipitates were analyzed with the form factor of a tri–axial ellipsoid. The size and long axis/short axis ratio of ellipsoidal precipitates could be evaluated from the scattering profiles.
