Nucleation and growth in Cu–0.7at.% Ti as studied with the tomographic atom probe

The early stages of nucleation in the system Cu–0.7at.% Ti were examined by means of field ion microscopy and the tomographic atom probe. The specimen was aged isothermally at 623 K for different times up to 720 h. The early stages of ageing indicate concentration fluctuations, which might be identified as the first stage of nucleation. The time evolution of the particle sizes and the particle number density are characterized and discussed in terms of the modified Langer–Schwartz model. Deviations from the predictions of this model can be found, especially for short ageing times.