Investigation of the early stages of decomposition of Cu-0.7at.% Fe with the tomographic atom probe

The early stages of precipitation of the Fe-rich phase in supersaturated Cu-Fe alloy were studied with the field ion microscope and the tomographic atom probe. The specimens of nominal composition Cu-0.7at.% Fe were homogenized at 1173 K and immediately aged in a salt bath for different times at 803 K to follow the decomposition path at this reaction temperature. In this work, preliminary results on the temporal evolution of the decomposition are presented. In particular, the particle radii and particle number density were determined as a function of the ageing time. At the initial stages of the decomposition concentration, fluctuations were observed, which could be quantitatively characterized. The decomposition sequence is discussed in terms of the nucleation and growth theory. (C) 2002 Elsevier Science B.V. All rights reserved.