Damage kinetics in high-temperature irradiated Ni crystals

• McChasy-1 and 2 codes were used to analyze the RBS/C spectra. • For the lowest fluence − small interstitial loops and 2–5 nm size SFT are present. • Above 7 × 10 15 cm −2 − bubbles with small and large SFTs are visible. • Additional step in damage kinetics revealed for the highest fluence (∼25 dpa) • The impact of the bubbles formed is noticeable for nanomechanical and RBS/C results. High-temperature (∼800 K) ion irradiation with 380 keV Ar ions was used to modify the surface of Ni single crystals in order to generate radiation defects and mimic the effect of neutrons avoiding sample activation. The modified 800 nm thick layer was analyzed regarding structural and mechanical properties utilizing a combination of experimental and simulation techniques. The ion implantation fluence ranged from 1 × 10 14 cm −2 up to 1 × 10 16 cm −2 , which corresponds to values of displacements per atom from 0.25 to 25, respectively. The structural characterization was performed by Rutherford Spectroscopy in Channeling mode (RBS/C) associated with scanning (SEM) and transmission electron microscopy (TEM). The experimental results were supported by Monte Carlo (McChasy) and Molecular Dynamics (MD-LAMMPS) simulations. The simulations performed using the second generation of the McChasy code show that the influence of bubbles formed inside the material is not negligible and affects the quantitative analysis of defects in the simulated spectra. A second step in damage kinetics was revealed for the highest dose (i.e., 25 dpa) as a consequence of the entanglement of dislocations and agglomeration of noble gas bubbles, which was confirmed by TEM analysis. Moreover, nanomechanical results confirm that Ar bubbles deteriorate mechanical properties such as hardness.