IRRADIATION-INDUCED SILICON SEGREGATION IN FERRITIC STEELS

Irradiation-induced segregation (IRS) of Si in ferritic steels has bee n modelled using a non-equilibrium segregation based method relying on describing the motion of point defect-solute complexes to grain bound aries. The model is extended from the earlier versions to account more accurately for composition changes occurring on the grain boundary pl ane and to account more properly for the temperature dependence of dis location density. The results of the model indicate strong peaking of IRS at certain critical temperatures. The peak positions move as the i rradiation conditions are altered and as certain microstructural featu res like grain size and dislocation density are changed. The model is applied in this paper to provide explanation for observed DBTT shifts after neutron irradiation of ferritic steels.