Small angle X-ray scattering (SAXS) studies were carried out in Shanghai Synchrotron Radiation Facility (SSRF) to study the effect of addition of TiB2 particles on the melt structures of Al-15 wt% Cu. It was found that doping with TiB2 particles could dramatically reduce the sizes of the melt aggregates at temperatures ranging from the melting point to 800 degrees C. The results show that the aggregates in the Al-Cu melt present mass fractal characteristics and distribution of incompact 3D flocs. (C) 2013 Elsevier B.V. All rights reserved.