Irradiation-induced grain and lath boundary segregation in ferritic-martensitic steels

The temperature dependence of irradiation-induced nonequilibrium segregation of Si and P to grain boundaries has been modelled in bcc ferritic iron, taken to represent ferritic-martensitic steels. The relevant point defect properties required for analysis are documented and the approximations used to circumvent lack of precise data on point defect formation, migration and solute binding energies highlighted. Analytical electron microscopy results are presented on solute segregation to lath boundaries in fast reactor irradiated FV448 martensitic steel, and compared with calculated behaviour. Predictions of enhanced interfacial Si segregation after irradiation at 400deg C are in accord with experimental observations. (orig.)