Modelling of copper precipitation in iron during thermal aging and irradiation

The cluster dynamics model for precipitation (CD-P model) described in [J. Nucl. Mater. 245 (1997) 224] has been improved and applied to copper precipitation in Fe–Cu and Fe–Cu–Ni during thermal aging at different temperatures. The CD-P model was tested on atom probe measurements [Mater. Sci. Eng. A 250 (1998) 49] and small angle neutron scattering (SANS) measurements [J. Nucl. Mater. 245 (1997) 224; Springer Proc. Phys. 10 (1986) 73]. Copper diffusivity was found to be a little higher than that proposed by Salje and Feller-Kniepmeier [J. Appl. Phys. 48 (1977) 1833]. The binding energy proposed in [J. Nucl. Mater. 277 (2000) 113] was also tested and it was concluded that little change occurs compared to the classical capillary model. Assuming a constant vacancy concentration (in other words a constant Cu diffusivity), the CD-P model was then applied to electron and neutron irradiation at 290 °C. In a second step, the CD-P model and the cluster dynamics model for vacancy and interstitial clustering (CD-VIC model) described in [J. Nucl. Mater. 302 (2002) 143] were mixed so as to really describe precipitation under irradiation by taking into account the evolution of vacancy concentration with time. The result is that the agreement between modelling and experimental data is better, specially in the case of neutron irradiation.