  In this study structural and mechanical properties of a 1 um thick Al2O3
coating, deposited on 316L stainless steel by Pulsed Laser Deposition (PLD),
subjected to high energy ion irradiation were assessed. Mechanical properties
of pristine and ion-modified specimens were investigated using the
nanoindentation technique. A comprehensive characterization combining
Transmission Electron Microscopy and Grazing-Incidence X-ray Diffraction
provided deep insight into the structure of the tested material at the nano-
and micro- scale. Variation in the local atomic ordering of the irradiated zone
at different doses was investigated using a reduced distribution function
analysis obtained from electron diffraction data. Findings from nanoindentation
measurements revealed a slight reduction in hardness of all irradiated layers.
At the same time TEM examination indicated that the irradiated layer remained
amorphous over the whole dpa range. No evidence of crystallization, void
formation or element segregation was observed up to the highest implanted dose.
Reported mechanical and structural findings were critically compared with each
other pointing to the conclusion that under given irradiation conditions, over
the whole range of doses used, alumina coatings exhibit excellent radiation
resistance. Obtained data strongly suggest that investigated material may be
considered as a promising candidate for next-generation nuclear reactors,
especially LFR-type, where high corrosion protection is one of the highest
prerogatives to be met.
