Nanoindentation testing of Si3N4 irradiated with swift heavy ions

Abstract We report the results of the nanoindentation tests of silicon nitride irradiated with Ar (46 MeV), Kr (107 MeV), Xe (167 MeV, 220 MeV) and Bi (710 MeV) ions. The behaviour of hardness with respect to ion fluence was analyzed and correlated with the microstructure evolution examined using transmission electron microscopy. Insignificant changes in hardness are observed for ion species (Ar, Kr) for which the electronic stopping power is less than the threshold of latent track formation. Accumulation of latent tracks produced by Xe and Bi ions results first in hardening and then, after track region overlapping and amorphization of the crystalline matrix, in softening of irradiated silicon nitride.