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(LID)/dD. was estimated to evaluate the depth dependent formation of hardening features in the model alloys irradiated with 12 MeV Ni ions at 300 degreesC 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. (C) 2002 Elsevier Science B.V. All rights reserved.