Studying crystallization of amorphous metal alloys by time-resolved EXAFS

The first complete observation of a temperature-induced crystallization process using time-resolved X-ray absorption spectroscopy (XAS) is presented. The sub-Tg reordering of a Ni60B40 amorphous alloy has been investigated, yielding a complete characterization from both the structural and kinetical points of view. This enabled the sharpening and shift of the Ni?Ni radial distribution function during the annealing to be quantified and the type of crystallization process to be determined; it was found to be an interface-governed growth of pre-existing nuclei. Theoretical estimates of the parameters of the crystallization kinetics confirm this interpretation of the data.