Formation of dislocations and hardening of LiF under high-dose irradiation with 5–21 MeV 12C ions

Abstract

The emergence of dislocations and hardening of LiF crystals irradiated to high doses with 12C ions have been investigated using chemical etching, AFM, nanoindentation, and thermal annealing. At fluences ensuring the overlapping of tracks (Ф ≥6 × 1011 ions/cm2), the formation of dislocation-rich structure and ion-induced hardening is observed. High-fluence (1015 ions/cm2) irradiation with 12C ions causes accumulation of extended defects and induces hardening comparable to that reached by heavy ions despite of large differences in ion mass, energy, energy loss, and track morphology. The depth profiles of hardness indicate on a notable contribution of elastic collision mechanism (nuclear loss) in the damage production and hardening. The effect manifests at the end part of the ion range and becomes significant at high fluences (≥1014 ions/cm2).