Evaluation of radiation hardening in Fe alloys under heavy ion irradiation by micro-indentation technique

To correlate micro-structural evolution near the surface under ion irradiation with macroscopic mechanical properties, micro-indentation tests were applied to heavy ion-irradiated model alloys of ferritic steels. The derivative of the load–displacement ratio with respect to the displacement, d(L/D)/dD, was estimated to evaluate the depth dependent formation of hardening features in the model alloys irradiated with 12 MeV Ni ions at 300 °C between 8 and 25 dpa. The depth distribution of radiation-enhanced formation of Cu precipitate in Fe–0.3Cu was found to change with dose, because of over-aging of the precipitates near the peak damage depth. Hardening near the peak damage depth region in Fe–0.3Cu–0.7Ni alloy increases with dose, indicating that the addition of Ni suppresses the growth of Cu-rich precipitates.