Experimental and theoretical analysis of equilibrium segregation and radiation-induced segregation of Cr at grain boundaries in a reduced activation ferritic/martensitic (RAFM) steel

Helium ion irradiation at 350 degrees C was performed to study equilibrium segregation and radiation-induced segregation (RIS) of Cr at grain boundaries in reduced activation ferritic/martensitic steels. Cr concentration at grain boundary was measured by scanning transmission electron microscopy with an energy-dispersive spectrometer. The measured Cr concentration at grain boundaries in heat treated zone was 11.7 and 12.8 wt.% in irradiated zone, respectively, which matched well to the calculated results from Mclean and modified Perk model. Equilibrium segregation and RIS of Cr mechanisms were theoretically analysed. The analysis indicates that as temperature rises, equilibrium Cr segregation decreases monotonically, while RIS of Cr has a bell-shape profile, which increases first and then decreases. It is also shown that at low and high temperatures, equilibrium segregation of Cr is higher than that of RIS; at intermediate temperatures, equilibrium Cr segregation is lower than RIS.

Automated summary

Helium ion irradiation at 350 degrees C was performed to study the equilibrium segregation and radiation-induced segregation of Cr at grain boundaries in reduced activation ferritic/martensitic steels. The Cr concentration at grain boundaries was measured and analyzed, with results indicating that as temperature rises, equilibrium Cr segregation decreases monotonically, while RIS of Cr has a bell-shaped profile, increasing first and then decreasing. It was also found that at low and high temperatures, equilibrium segregation of Cr is higher than RIS; at intermediate temperatures, equilibrium Cr segregation is lower than RIS.