Effects of Ti element on the microstructural stability of 9Cr-WVTiN reduced activation martensitic steel under ion irradiation

Microstructure of 9Cr-WVTiN reduced-activation martensitic steels with two different Ti concentrations irradiated with Fe+, He+ and H+ at 300 °C was studied with transmission electron microscopy. Small dislocation loops were observed in the irradiated steels. The mean size and number density of dislocation loops decreased with the increase of Ti concentration. The segregation of Cr and Fe in carbides was observed in both irradiated steels, and the enrichment of Cr and depletion of Fe were more severe in the low Ti-concentration 9Cr-WVTiN steel.