Surface segregation and radiation hardening of 16Cr12MoWSiVNbB steel after irradiation with Ni++ and He+ ions

Irradiation of EP-823 (16Cr12MoWsiVNbB) ferritic-martensitic steel with 7-MeV Ni⁺⁺ ions and with 30- and 70-keV He⁺ ions at a temperature of 500°C was followed by an increase in the microhardness, which was due to both radiation point defects and changes in the phase composition and the dislocation structure of the steel. It was found that the dependence of the largest relative increase in the microhardness on the concentration of radiation-induced point defects in the near-surface region of the steel under irradiation with different ions correlated with an analogous dependence of the surface segregation of silicon and chromium.