Evaluation of irradiation hardening and deformation in bcc and fcc metals after ion irradiation

Abstract

The nanoindentation technology is estimated to evaluate irradiation hardening and deformation characteristics of ion-irradiated bcc and fcc metals. The specimens are irradiated with 8MeV $Fe^{+4}$ ions to 0.15dpa and 1.5dpa at 60℃. The hardness value profile shows depth dependence of the hardness value in bcc and fcc metals. In L/D and D plot, the pop-in phenomenon is able to estimate radiation defects at the peak displacement damage depth and irradiation hardening due to radiation-induced defects. The result of the hardness ratio increasing with doses means dose dependence of irradiation hardening in all specimens, before and after irradiation. The derivative of the load-to-depth ratio, d(L/D)/dD, is evaluated for the depth-dependent deformation characteristics in irradiated specimens. This profile shows that a depth at the peak plastic deformation is 0.01-0.02 times the depth at the peak displacement damage and the peak value of the deformation parameter moves to the specimen surface with increasing doses.