The structure of Al-26 mass% Si-8 mass% Ni alloy, a material used as an input product for manufacturing light weight products via powder metallurgy, was investigated by in situ powder diffraction techniques up to 700° C. Thermal expansion of the dominant phases indicates substitutional alloying of silicon by nickel atoms, forming a solid solution phase stable in the temperature region from 330 to 550° C. The presence of Al, Si, Al3Ni and Si3Ni was determined by phase analysis from a sample annealed at 700° C (re-melted) and cooled down to room temperature. EXAFS analysis of as prepared and re-melted samples documented similar local atomic structure around the Ni atoms in both stages. (C) 2005 Springer Science + Business Media, Inc.